US20080180604A1 - Television set using liquid crystal display apparatus having improved viewing angle - Google Patents
Television set using liquid crystal display apparatus having improved viewing angle Download PDFInfo
- Publication number
- US20080180604A1 US20080180604A1 US12/009,928 US992808A US2008180604A1 US 20080180604 A1 US20080180604 A1 US 20080180604A1 US 992808 A US992808 A US 992808A US 2008180604 A1 US2008180604 A1 US 2008180604A1
- Authority
- US
- United States
- Prior art keywords
- liquid crystal
- layer
- polarizing
- retardation
- viewing angle
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Images
Classifications
-
- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on liquid crystals, e.g. single liquid crystal display cells
- G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
- G02F1/1333—Constructional arrangements; Manufacturing methods
- G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
- G02F1/13363—Birefringent elements, e.g. for optical compensation
-
- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on liquid crystals, e.g. single liquid crystal display cells
- G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
- G02F1/1333—Constructional arrangements; Manufacturing methods
- G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
- G02F1/13363—Birefringent elements, e.g. for optical compensation
- G02F1/133634—Birefringent elements, e.g. for optical compensation the refractive index Nz perpendicular to the element surface being different from in-plane refractive indices Nx and Ny, e.g. biaxial or with normal optical axis
-
- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on liquid crystals, e.g. single liquid crystal display cells
- G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
- G02F1/1333—Constructional arrangements; Manufacturing methods
- G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
-
- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on liquid crystals, e.g. single liquid crystal display cells
- G02F1/137—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on liquid crystals, e.g. single liquid crystal display cells characterised by the electro-optical or magneto-optical effect, e.g. field-induced phase transition, orientation effect, guest-host interaction or dynamic scattering
- G02F1/139—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on liquid crystals, e.g. single liquid crystal display cells characterised by the electro-optical or magneto-optical effect, e.g. field-induced phase transition, orientation effect, guest-host interaction or dynamic scattering based on orientation effects in which the liquid crystal remains transparent
- G02F1/1396—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on liquid crystals, e.g. single liquid crystal display cells characterised by the electro-optical or magneto-optical effect, e.g. field-induced phase transition, orientation effect, guest-host interaction or dynamic scattering based on orientation effects in which the liquid crystal remains transparent the liquid crystal being selectively controlled between a twisted state and a non-twisted state, e.g. TN-LC cell
-
- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F2203/00—Function characteristic
- G02F2203/66—Normally white display, i.e. the off state being white
-
- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F2413/00—Indexing scheme related to G02F1/13363, i.e. to birefringent elements, e.g. for optical compensation, characterised by the number, position, orientation or value of the compensation plates
- G02F2413/10—Indexing scheme related to G02F1/13363, i.e. to birefringent elements, e.g. for optical compensation, characterised by the number, position, orientation or value of the compensation plates with refractive index ellipsoid inclined, or tilted, relative to the LC-layer surface O plate
- G02F2413/105—Indexing scheme related to G02F1/13363, i.e. to birefringent elements, e.g. for optical compensation, characterised by the number, position, orientation or value of the compensation plates with refractive index ellipsoid inclined, or tilted, relative to the LC-layer surface O plate with varying inclination in thickness direction, e.g. hybrid oriented discotic LC
Definitions
- the present invention relates to a television receiver to receive broadcast waves to display pictures.
- a flat-screen liquid crystal television receiver using a liquid crystal display device to reduce its depth is known as a broadcasting receiver that receives a television broadcast to display its pictures.
- Liquid crystal display devices used in this liquid crystal television receiver include a twisted nematic type liquid crystal display device (a TN liquid crystal display device) in which liquid crystal molecules are twist-aligned between substrates facing each other, a vertical alignment type liquid crystal display device (VA) having a liquid crystal layer in which liquid crystal molecules are vertically initially aligned between substrates, an in-plane switching type liquid crystal device (IPS) in which directions of liquid crystal molecules are controlled within a plane parallel to substrate surfaces, and others.
- a twisted nematic type liquid crystal display device a twisted nematic type liquid crystal display device
- VA vertical alignment type liquid crystal display device
- IPS in-plane switching type liquid crystal device
- liquid crystal display device that includes a liquid crystal cell including a liquid crystal layer in which liquid crystal molecules are twist-aligned at a twisted angle of substantially 90° between a pair of substrates, and a pair of polarizing plates arranged to sandwich this liquid crystal cell therebetween, wherein one of the pair of polarizing plates is arranged in such a direction that an absorption axis is set to parallel with a direction crossing an aligning treatment direction of one substrate of the liquid crystal cell at 45° (see JP-A 2006-285220 (KOKAI)).
- This TN liquid crystal display device enhances contrast and improves grayscale inversion in an intermediate gradation. Further, in this liquid crystal display device, viewing angle compensating plates are respectively arranged between the liquid crystal cell and the pair of polarizing plates, and arranging a retardation plate improves viewing angle characteristics. Further, since these TN liquid crystal display devices have simple structures and matured manufacturing processes, they are good display devices allowed to be mass-produced with stable characteristics.
- the TN type liquid crystal display device has large viewing angle dependency of a transmittance as a television receiver observed from various directions, and hence sufficiently wide viewing angle characteristics cannot be obtained.
- An object of the present invention is to provide a liquid crystal display apparatus and a broadcasting receiving apparatus having a wide viewing angle with improved viewing angle dependency of a transmittance.
- a liquid crystal display apparatus includes a liquid crystal display device.
- the liquid crystal display device includes:
- a liquid crystal cell including a pair of substrates in which at least one electrode and an alignment film covering the electrode are provided on each of inner surfaces of the substrates facing each other, and a liquid crystal layer that is sandwiched between the substrates and includes liquid crystal molecules twist-aligned;
- each of the polarizing plates including a polarizing layer having a transmission axis allowing transmission of linear polarized light and an absorption axis in a direction perpendicular to the transmission axis, and at least one base film to support the polarizing layer;
- each of the viewing angle compensating layers having a phase difference within a plane parallel to substrate surfaces of the liquid crystal cell and a phase difference within a plane perpendicular to the substrate surfaces.
- a total value of retardations in a thickness direction each of which is a product of a phase difference within a plane perpendicular to the substrate surfaces and a layer thickness, of a plurality of optical layers between the first and second polarizing layers, including at least the first and second viewing angle compensating layers but excluding the liquid crystal layer, is set to a value that cancels out a retardation in a liquid crystal layer thickness direction, which is a product of a phase difference within a plane perpendicular to the substrate surfaces and a liquid crystal layer thickness, of the liquid crystal layer when a voltage sufficiently high to raise and align the liquid crystal molecules with respect to the substrate surfaces is applied to the liquid crystal layer between the electrodes of the first and second substrates.
- the liquid crystal display apparatus further includes a display driving section to supply signals to electrodes formed on a pair of substrates and to drive the liquid crystal display device based on picture data supplied from the outside.
- a broadcasting receiving apparatus includes:
- a broadcasting receiving section to receive broadcasted broadcast waves and to demodulate the received waves to output a demodulation signal having at least picture data and audio data;
- an picture/audio data generating section to separate the picture data and the audio data from the demodulation signal output from the broadcasting receiving section and to output a picture data and an audio data based on the demodulation signal;
- a picture display section to drive a plurality of pixels aligned in a matrix based on the picture data supplied from the picture/audio data generating section to display pictures;
- the liquid crystal display device includes:
- a first substrate having, on one surface thereof, at least one first electrode and an alignment film covering the first electrode;
- a second substrate that is arranged to face an electrode formation surface of the first substrate, and has, on a surface thereof facing the first substrate, a plurality of second electrodes in which regions respectively facing the first electrode form a plurality of pixels aligned in a matrix to form images and an alignment film covering these electrodes;
- liquid crystal layer that is sandwiched between the first and second substrates and includes liquid crystal molecules twist-aligned at substantially 90°;
- each of the polarizing plates including a polarizing layer having a transmission axis allowing transmission of linear polarized light and an absorption axis in a direction perpendicular to the transmission axis, and at least one base film to support the polarizing layer;
- each of the viewing angle compensating plates having a phase difference within a plane parallel to substrate surfaces of the liquid crystal cell and a phase difference within a plane perpendicular to the substrate surfaces, and
- a total value of retardations in a thickness direction each of which is a product of a phase difference within a plane perpendicular to the substrate surfaces and a layer thickness, of a plurality of optical layers between the first and second polarizing layers, including at least the first and second viewing angle compensating plates but excluding the liquid crystal layer, is set to a value that cancels out a retardation in a liquid crystal layer thickness direction, which is a product of a phase difference within a plane perpendicular to the substrate surfaces and a liquid crystal layer thickness, of the liquid crystal layer when a voltage sufficiently high to raise and align the liquid crystal molecules with respect to the substrate surfaces is applied between the electrodes of the first and second substrates.
- the broadcasting receiving apparatus further includes an audio generating section to generate the audio signal based on the audio data supplied from the picture/audio data generating section and to produce audio from the audio signal.
- a broadcasting receiving apparatus includes:
- a broadcasting receiving section to receive broadcasted broadcast waves and to demodulate the received waves to output a demodulation signal having at least picture data and audio data;
- an picture/audio data generating section to separate the picture data and the audio data from the demodulation signal output from the broadcasting receiving section and to output a picture data and an audio data based on the demodulation signal;
- a picture display section to drive a plurality of pixels aligned in a matrix based on the picture data supplied from the picture/audio data generating section to display pictures;
- the liquid crystal display device includes:
- a first substrate having, on one surface thereof, at least one electrode and a first alignment film covering the first electrode and subjected to an aligning treatment in a predetermined first direction;
- a second substrate that is arranged to face an electrode formation surface of the first electrode, and has, on a surface thereof facing the first substrate, a plurality of second electrodes in which regions respectively facing the first electrode form a plurality of pixels aligned in a matrix to form images and a second alignment film covering the second electrode and subjected to an aligning treatment in a second direction crossing the first direction at an angle of substantially 90°;
- liquid crystal layer that is sandwiched between the first alignment film of the first substrate and the second alignment film of the second substrate and includes liquid crystal molecules twist-aligned between the first alignment film and the second alignment film at a twisted angle of substantially 90°;
- a first polarizing layer that is arranged to face an outer surface opposite to the electrode formation surface of the first substrate and has an absorption axis in a direction crossing an aligning treatment direction of the first alignment film at an angle of substantially 45°;
- a second polarizing layer that is arranged to face an outer surface opposite to an electrode formation surface of the second substrate and has an absorption axis in a direction substantially perpendicular to or substantially parallel to the absorption axis of the first polarizing layer;
- each viewing angle compensating layer that are respectively arranged between the first substrate and the first polarizing layer and between the second substrate and the second polarizing layer, each viewing angle compensating layer having a phase difference within a plane parallel to substrate surfaces of the first and second substrates and a phase difference within a plane perpendicular to the substrate surfaces.
- a retardation Rth in a thickness direction is set to the range satisfying the following expression:
- a thickness direction perpendicular to the substrate surfaces is a Z axis
- nx is a refractive index in the X axis direction
- ny is a refractive index in the Y axis direction
- nz is a refractive index in the Z axis direction
- d is a layer thickness of the optical layer
- Rthi is a retardation in the thickness direction of each optical layer represented as ⁇ (nx+ny)/2 ⁇ nz ⁇ d
- Rth is the retardation in the thickness direction obtained by adding values of the retardations Rthi in the thickness direction of the respective optical layers
- ⁇ nd is a product of an anisotropic refractive index ⁇ n of a liquid crystal material constituting the liquid crystal layer and a liquid crystal thickness d;
- the broadcasting receiving apparatus further includes an audio generating section to generate the audio signal based on the audio data supplied from the picture/audio data generating section and to produce audio from the audio signal.
- FIG. 1 is a schematic perspective view of a broadcasting receiving apparatus showing a first embodiment according to the present invention
- FIG. 2 is a schematic perspective view showing a structure of a liquid crystal display apparatus used in the broadcasting receiving apparatus according to the first embodiment
- FIG. 3 is a schematic block diagram showing a structure of, the broadcasting receiving apparatus showing the first embodiment
- FIG. 4 is a block diagram showing a liquid crystal display apparatus used in the broadcasting receiving apparatus according to the first embodiment
- FIG. 5 is a schematic cross-sectional view of a liquid crystal display device showing a first embodiment of the present invention
- FIG. 6 is an enlarged cross-sectional view of a part of a liquid crystal cell
- FIG. 7 is an enlarged cross-sectional view of a part of a viewing angle compensating plate
- FIG. 8 is a view showing aligning treatment directions of first and second alignment films, directions of absorption axes of first and second polarizing layers, and directions of optical axes of first and second viewing angle compensating layers in the first embodiment;
- FIG. 9 is a view showing a relationship between a ratio of liquid crystal layer thicknesses d R , d G , and d B of pixel portions of respective colors, i.e., red, green, and blue and a display chromaticity when white is displayed in the liquid crystal display device according to the first embodiment;
- FIG. 10 is a view showing a relationship between ⁇ nd of a liquid crystal layer and a retardation Rth LC in a thickness direction of the liquid crystal layer when a saturation voltage is applied in the liquid crystal display device according to the first embodiment;
- FIG. 11 is a view showing a relationship between an in-plane retardation Ro, ⁇ nd of the liquid crystal layer, and a transmittance, the in-plane retardation Ro being obtained by adding respective in-plane retardation values of base films of a plurality of optical layers between the first and second polarizing layers excluding the liquid crystal layer in the liquid crystal display device according to the first embodiment;
- FIGS. 12A to 12D are viewing angle characteristic views at the time of white display T W , black display T B , 50% gradation (a gradation with 50% brightness of white display) display T 50 , and 20% gradation (a gradation with 20% brightness of white display) display T 20 in the liquid crystal display device according to the first embodiment;
- FIGS. 13A to 13D are viewing angle characteristic views at the time of white display T W , black display T B , 50% gradation (a gradation with 50% brightness of white display) display T 50 , and 20% gradation (a gradation with 20% gradation of white display) display T 20 in the liquid crystal display device according to a modification of the first embodiment;
- FIG. 14 is a schematic cross-sectional view of a liquid crystal display device used in a second embodiment of the present invention.
- FIG. 15 is a view showing aligning treatment directions of first and second alignment films, directions of absorption axes of first and second polarizing layers, directions of optical axes of first and second viewing angle compensating layers, and directions of retardation axes of first and second retardation plates in the liquid crystal display device according to the second embodiment;
- FIGS. 16A to 16D are viewing angle characteristic views at the time of white display T W , black display T B , 50% gradation (a gradation with 50% brightness of white display) display T 50 , and 20% gradation (a gradation with 20% brightness of white display) of display T 20 in the liquid crystal display in the liquid crystal display device according to the second embodiment;
- FIG. 17 is a schematic cross-sectional view of a liquid crystal display device used in a third embodiment according to the present invention.
- FIG. 18 is a perspective view for explaining characteristics of an optical film in the liquid crystal display device according to the third embodiment.
- FIG. 19 is a view showing aligning treatment directions of first and second alignment films, directions of absorption axes of first and second polarizing layers, directions of optical axes of first and second viewing angle compensating layers, directions of retardation axes of first and second retardation plates, directions of optical axes of first and second optical films;
- FIGS. 20A to 20D are viewing angle characteristic views at the time of white display T W , black display T B , 50% gradation (a gradation with 50% brightness of white display) display T 50 , and 20% gradation (a gradation with 20% brightness of white display) display T 20 in the liquid crystal display device according to the third embodiment;
- FIG. 21 is a schematic cross-sectional view of a liquid crystal display device used in a fourth embodiment of the present invention.
- FIG. 22 is a view showing aligning treatment directions of first and second alignment films, directions of absorption axes of first and second polarizing layers, directions of optical axes of first and second viewing angle compensating layers, directions of retardation axes of first and second retardation plates, and directions of optical axes of optical films in the liquid crystal display device according to the fourth embodiment;
- FIGS. 23A to 23D are viewing angle characteristic views at the time of white display T W , black display T B , 50% gradation (a gradation with 50% brightness of white display) display T 50 , and 20% gradation (a gradation with 20% brightness of white display) display T 20 in the liquid crystal display device according to the fourth embodiment;
- FIG. 24 is a schematic cross-sectional view of a liquid crystal display device used in a fifth embodiment of the present invention.
- FIG. 25 is a view showing aligning treatment directions of first and second alignment films, directions of absorption axes of first and second polarizing layers, directions of optical axes of first and second viewing angle compensating layers, and directions of retardation axes of first and second retardation plates in the liquid crystal display device according to the fifth embodiment;
- FIGS. 26A to 26D are viewing angle characteristic views at the time of white display T W , black display T B , 50% gradation (a gradation with 50% brightness of white display) display T 50 , and 20% gradation (a gradation with 20% brightness of white display) display T 20 in the liquid crystal display device according to the fifth embodiment;
- FIG. 27 is a schematic cross-sectional view of a liquid crystal display device used in a sixth embodiment according to the present invention.
- FIG. 28 is a view showing aligning treatment directions of first and second alignment films, directions of absorption axes of first and second polarizing layers, directions of optical axes of first and second viewing angle compensating layers, and directions of retardation axes of first and second retardation plates in the liquid crystal display device according to the sixth embodiment;
- FIGS. 29A to 29D are viewing angle characteristic views at the time of white display T W , black display T B , 50% gradation (a gradation with 50% brightness of white display) display T 50 , and 20% gradation (a gradation with 20% brightness of white display) display T 20 in the liquid crystal display device according to the sixth embodiment;
- FIG. 30 is a schematic cross-sectional view of a liquid crystal display device used in a seventh embodiment according to the present invention.
- FIG. 31 is a view showing aligning treatment directions of first and second alignment films, directions of absorption axes of first and second polarizing layers, directions of optical axes of first and second viewing angle compensating layers, and directions of retardation axes of first and second retardation plates in the liquid crystal display device according to the seventh embodiment;
- FIGS. 32A to 32D are viewing angle characteristic views at the time of white display T W , black display T B , 50% gradation (a gradation with 50% brightness of white display) display T 50 , and 20% gradation (a gradation with 20% brightness of white display) display T 20 in the liquid crystal display device according to the seventh embodiment.
- FIGS. 1 to 4 show a structure of a television broadcasting receiver in a first embodiment according to the present invention.
- a broadcasting receiver 200 includes a window 202 formed on a front surface of a housing 201 in accordance with a liquid crystal display device, and speakers 300 to produce audio, which are arranged on both sides of the window 202 .
- a switch group 400 including, e.g., a power supply switch, a channel changeover switch, and a volume adjustment switch, is arranged on an upper portion of the housing 201 .
- An antenna 500 to receive broadcast waves is arranged on a rear surface of the housing 201 .
- a liquid crystal display device 100 which is arranged in accordance with the window 202 of the housing 201 , includes a pair of substrates 2 and 3 facing each other and optical plates 102 and 103 that are arranged on both sides of the pair of substrates, each of the optical plates being obtained by stacking a later-explained polarizing plate, a viewing angle compensating plate, and an optical layer formed of various kinds of retardation plates.
- a backlight 600 is arranged on an opposite side of an observation side of this liquid crystal display device 100 .
- This backlight 600 includes a light guiding plate 601 , an optical film 602 , which may include a diffusion film and a prism sheet, arranged on surface of the light guiding plate 601 on the liquid crystal display device 100 side, a reflection film 603 arranged on the opposite side of the observation side of the light guiding plate 601 , and a plurality of light sources 604 , which may be LEDs, aligned on an end face 611 of the light guiding plate 601 .
- This backlight 600 introduces light emitted from the plurality of light sources 604 to the light guiding plate 601 from the end face 611 , causing the light to propagate within the light guiding plate 601 .
- the light that has exited from the opposite side of the observation side of the light guiding plate 601 is reflected by the reflection film 603 to again enter the light guiding plate 601 , and the light that has exited from an exit surface of the light guiding plate 601 facing the liquid crystal display device 100 .
- the light that has exited from the exit surface of the light guiding plate 601 is diffused by the diffusion film of the optical film 602 to become light having uniform brightness, and is directed toward the liquid crystal display device 100 by the prism sheet.
- the liquid crystal display device 100 performs transmission type display by using the light exiting the backlight 600 .
- FIG. 3 shows a structure of a television receiver that receives digital broadcasting in this first embodiment.
- a television receiver 200 includes an antenna 500 to receive broadcast waves including a broadcasting signal containing picture data and audio data and a transmission control signal for, e.g., a transmission parameter transmitted from a broadcasting station, a tuner section 501 to which the broadcast waves received by this antenna 500 are supplied, a demodulating section 502 to demodulate the broadcasting signal taken out by this tuner section 501 , a picture/audio decoding processing section 503 to decode the demodulated broadcasting signal, a display driving section 504 to drive the liquid crystal display device 100 based on the decoded picture data, an audio signal generating section 505 to generate an audio signal based on the audio data and to drive the speakers 300 , a transmission parameter holding section 506 to store a parameter, and a control section 507 to control operations of these respective sections.
- a broadcasting signal containing picture data and audio data and a transmission control signal for, e.g.
- the transmission parameter holding section 506 sets a parameter as information required to take out a frequency of a specified channel in the tuner section 501 .
- the picture/audio decoding processing section 503 separates picture data and audio data from the demodulated broadcasting signal, and decodes the compressed and/or shuffled data to output the picture data and the audio data.
- the tuner section 501 takes out a frequency of a specified channel from a digital broadcasting signal received by the antenna 500 based on a parameter set by reading the parameter of the specified channel from the transmission parameter holding section 506 by the control section 507 .
- the demodulating section 502 takes out a clock signal included in the digital broadcasting signal having the frequency taken out by the tuner section 501 to demodulate the digital broadcasting signal, and outputs a transport stream.
- the picture/audio decoding processing section 503 decodes the transport stream to output the picture data and the audio data.
- the picture data output from a picture/audio data generating section including the picture/audio decoding processing section 503 is supplied to a picture display section including the display driving section 504 and the liquid crystal display device 100 , a driving signal associated with the picture data is generated by the display driving section 504 , and this driving signal is supplied to the liquid crystal display device 100 , thereby displaying a picture.
- the audio data output from the picture/audio decoding processing section 503 is supplied to an audio generating section including the audio signal generating section 505 and the speakers 300 , an audio signal is generated by the audio signal generating section 505 , and the speakers are driven based on this audio signal, thereby reproducing audio.
- the picture display section includes the liquid crystal display device 100 , a data line driving circuit 534 , a scan line driving circuit 524 , a opposed electrode driving circuit 544 , and a driving control circuit 514 to control operations of these circuits.
- the liquid crystal display device 100 in this embodiment is, e.g., an active matrix type liquid crystal display device, and includes a liquid crystal cell including a pair of substrates in which at least one electrode and an alignment film covering the electrode are provided on each of inner surfaces of the substrates, and a liquid crystal layer that is sandwiched between the substrates and includes liquid crystal molecules twist-aligned at substantially 90°.
- One of the pair of substrates is provided with, on its substrate surface, at least one opposed electrode, and the other substrate is provided with, on its substrate surface facing the opposed electrode, a plurality of pixel electrodes in which regions respectively facing the opposed electrode form a plurality of pixels aligned in a matrix to form images.
- a plurality of thin film transistors formed of TFTs associated with the pixel electrodes are arranged on the other substrate, and a plurality of data lines 110 connecting drain electrodes of the thin film transistors in accordance with each column and a plurality of gate lines 120 connecting gate electrodes of the thin film transistors in accordance with each row are arranged.
- the data lines 110 of the liquid crystal display device 100 are respectively connected with the data driving circuit 534 , the gate lines 120 are respectively connected with the scan line driving circuit 524 , and the opposed electrode is connected with the opposed electrode driving circuit 544 .
- the driving control circuit 514 generates an image signal based on picture data supplied from the picture/audio decoding processing section 503 , and supplies it together with a control signal, e.g., a clock signal to the data line driving circuit 534 .
- the data line driving circuit 534 generates a driving signal associated with each data line 110 based on the supplied image signal, and applies it to each data line 110 .
- the scan line driving circuit 524 generates a scan signal associated with each scan line 120 based on the control signal supplied from the driving control circuit 514 , and supplies it to each gate line 120 .
- the plurality of gate lines 120 are sequentially scanned by the scan line driving circuit 524 , the driving signal corresponding to the picture data is supplied to each data line 110 from the data line driving circuit 534 in synchronization with this scanning, and a voltage associated with the driving signal is applied to each pixel, thereby displaying a desired picture.
- FIGS. 5 to 12 show a detailed structure of a liquid crystal display device used in a first embodiment according to the present invention
- FIG. 5 is a schematic cross-sectional view of the liquid crystal display device.
- This liquid crystal display device is a TN type liquid crystal display device including a liquid crystal cell 1 including a nematic liquid crystal layer 10 in which liquid crystal molecules are twist-aligned at a twisted angle of substantially 90° sandwiched between a pair of transparent substrates 2 and 3 , a pair of first and second polarizing plates 11 and 15 arranged to sandwich this liquid crystal cell 1 , and first and second viewing angle compensating plates 19 and 22 respectively arranged between the liquid crystal cell 1 and the pair of polarizing plates 11 and 15 .
- FIG. 6 is an enlarged cross-sectional view of a part of the liquid crystal cell 1 .
- This liquid crystal cell 1 includes a first substrate 2 , a second substrate 3 arranged to face this first substrate, and a liquid crystal layer 10 arranged between the first and second substrates.
- the first substrate 2 has at least one first transparent electrode 4 and a first alignment film 7 that covers the first electrode 4 and is subjected to aligning treatment in a predetermined first direction, the first transparent electrode 4 and the first alignment film 7 being provided on one surface thereof.
- the second substrate 3 is arranged to face an electrode formation surface of the first substrate 2 , and has at least one second transparent electrode 5 facing the first electrode 4 , and a second alignment film 8 that covers the second transparent electrode 5 and is subjected to an aligning treatment in a second direction crossing the first direction for covering the second electrode 5 at an angle of substantially 90°, the second transparent electrode 5 and the second alignment film 8 being provided on a surface facing the first substrate 2 .
- the liquid crystal layer 10 is sandwiched between the first alignment film 7 and the second alignment film 8 , and liquid crystal molecules 10 a are twist-aligned at a twisted angle of substantially 90° between the first alignment film 7 and the second alignment film 8 .
- This liquid crystal layer 10 optically rotates a polarized light that has entered in an initial alignment state of liquid crystal molecules 10 a at 90°. Moreover, this liquid crystal layer 10 apparently changes a value of a retardation produced with respect to transmitted light within the range of substantially ⁇ /2 in accordance with an alignment state of the liquid crystal molecules 10 a.
- This liquid crystal cell 1 is an active matrix liquid crystal cell
- the electrode 4 provided on the substrate (which will be referred to as a rear substrate hereinafter) 2 located on an opposite side of a display observation side, is formed of a plurality of pixel electrodes aligned in a matrix, in a row direction (a lateral direction of a screen) and a column direction (the lateral direction of the screen).
- the electrode 5 provided on the other substrate (which will be referred to as a front substrate hereinafter) 3 located on the observation side, is a single-film-like opposed electrode formed to face an entire arrangement region of the plurality of pixel electrodes 4 .
- a plurality of TFTs (thin film transistors) respectively arranged in accordance with the plurality of pixel electrodes 4 , a plurality of scanning lines through which gate signals are supplied to the plurality of TFTs in respective rows, and a plurality of signal lines through which data signals are supplied to the plurality of TFTs in respective columns are provided on a surface of the rear substrate 2 facing the front substrate 3 .
- the TFT includes a gate electrode formed on the rear substrate 2 , a gate insulating film formed to cover the gate electrode, an i-type semiconductor film formed on the gate insulating film to face the gate electrode, and a drain electrode and a source electrode formed on both side portions of the i-type semiconductor film through an n-type semiconductor film.
- the gate electrode is connected with the scanning line
- the drain electrode is connected with the signal line
- the source electrode is connected with the corresponding pixel electrode 4 .
- color filters 6 R, 6 G, and 6 B of three colors i.e., red, green, and blue are provided on a surface of the front substrate 3 facing the rear substrate 2 in accordance with a plurality of pixels formed of regions where the plurality of pixel electrodes 4 face the opposed electrode 5 , and the opposed electrode 5 is provided to cover the color filters 6 R, 6 G, and 6 B.
- the pair of substrates 2 and 3 are arranged to face each other with a predetermined gap provided therebetween, and bonded to each other through a sealing member 9 (see FIG. 5 ) formed into a frame shape surrounding an arrangement region of the plurality of pixel electrodes 4 .
- the liquid crystal layer 10 is encapsulated in a region between the pair of substrates 2 and 3 surrounded by the sealing member 9 .
- the green filter 6 G is formed to be thicker than the red filter 6 R and the blue filter 6 B is formed with a larger film thickness than that of the green filter 6 G, so that a liquid crystal layer thickness d R of one of the pixels to which the red filter 6 R is provided, a liquid crystal layer thickness d G of one of the pixels to which the green filter 6 G is provided, and a liquid crystal layer thickness d B of one of the pixels to which the blue filter 6 B is provided have a relationship of d R ⁇ d G ⁇ d B .
- the first polarizing plate 11 arranged to face an outer surface of the liquid crystal cell 1 opposite to the electrode formation surface of the rear substrate 2 is arranged so that its absorption axes is set to parallel with a direction crossing an aligning treatment direction of the first alignment film 7 formed on the rear substrate 2 at an angle of substantially 45°.
- the second polarizing plate 15 arranged to face an outer surface of the liquid crystal cell 1 opposite to the electrode formation surface of the substrate 3 is arranged so that its absorption axes is set to parallel with a direction crossing the aligning treatment direction of the second alignment film 8 formed on the front substrate 3 at an angle of substantially 45°. That is, the absorption axes of the first polarizing plate 11 and the second polarizing plate 15 are perpendicular to each other.
- the first polarizing plate 11 includes a first polarizing layer 12 having an absorption axes in a direction crossing the aligning treatment direction of the first alignment film 7 at an angle of substantially 45°, and a pair of base films 13 and 14 that are respectively formed on both surfaces of the first polarizing layer 12 to sandwich the first polarizing layer 12 therebetween, have a phase difference in a plane parallel to substrate surfaces of the pair of substrates 2 and 3 being substantially zero, have a phase difference in a plane perpendicular to the substrate surfaces of the pair of substrates 2 and 3 (which will be referred to as a phase difference in a thickness direction thereinafter), and are formed of a transparent resin film, e.g., a TAC (triacetylcellulose) film.
- TAC triacetylcellulose
- the second polarizing plate 15 includes a second polarizing layer 16 having an absorption axis in a direction crossing the aligning treatment direction of the second alignment film 8 formed on the front substrate 8 at an angle of substantially 45°, and a pair of base films 17 and 18 that are provided on both surfaces of the second polarizing layer 16 to sandwich this second polarizing layer 16 therebetween, have a phase difference in a plane parallel to the substrate surfaces being substantially zero, have a phase difference in a plane perpendicular to the substrates (a phase difference in the thickness direction), and are formed of a transparent resin film, e.g., a TAC film.
- a transparent resin film e.g., a TAC film.
- the first and second viewing angle compensating plates 19 and 22 which are respectively arranged between the liquid crystal cell 1 and the pair of polarizing plates 11 and 15 , respectively include viewing angle compensating layers 20 and 23 formed of a discotic liquid crystal layer in which discotic liquid crystal molecules are hybrid-aligned, and a pair of base films 21 and 24 that are formed of a transparent resin film, e.g., the TAC film, the base films 21 being provided on at least one surface of the viewing angle compensating layers 20 and the base films 24 being provided on at least one surface of the viewing angle compensating layers 23 .
- a transparent resin film e.g., the TAC film
- Each of the viewing angle compensating layers 20 and 23 has a phase difference in a plane parallel with the substrate surfaces and a phase difference in a plane perpendicular to the substrate surfaces (a phase difference in the thickness direction). Furthermore, each of the pair of base films 21 and 24 has a phase difference in a plane parallel with the substrate surfaces being substantially zero and a phase difference in a plane perpendicular to the substrate surfaces (a phase difference in the thickness direction).
- the first and second viewing angle compensating plates 19 and 22 used in this embodiment are obtained by providing the base film 21 and 24 on one surface of the viewing angle compensating layer 20 and 23 , respectively.
- FIG. 7 is an enlarged cross-sectional view of a part of the first and second viewing angle compensating plates 19 and 22 , and the base films 21 and 24 are respectively provided with alignment films 21 a and 24 a that are subjected to an aligning treatment in one direction, the alignment film 21 a being formed on one surface of the base film 21 and the alignment film 24 a being formed on one surface of the base film 24 , and the discotic liquid crystal layers are respectively provided on the alignment films 21 a and 24 a .
- the discotic liquid crystal molecules 25 are hybrid-aligned so that a molecular axis perpendicular to discotic surfaces of the discotic liquid crystal molecules 25 is placed on a plane perpendicular to a film surface of the base film 21 and parallel to the aligning treatment direction of the alignment film 21 a and a tilt angle with respect to the base film 21 is sequentially increased from the base film 21 side toward its opposite side.
- Each of the viewing angle compensating layer 20 and 23 of the first and second viewing angle compensating plate 19 and 22 has a negative optical anisotropy having an optical axis providing a minimum refractive index in an average tilt direction of the molecular axis in the plane where the molecular axes of the hybrid-aligned discotic liquid crystal molecules 25 are present.
- a line on which the plane where the molecular axes of the discotic liquid crystal molecules 25 are present crosses the surface of the viewing angle compensating layer 20 and 23 is referred to as an optical axis direction.
- the first viewing angle compensating plate 19 is arranged so that a surface of the first viewing angle compensating layer 20 of this viewing angle compensating plate 19 where a tilt angle of the discotic liquid crystal molecules 25 is large (a surface opposite to the base film 21 side) faces the outer surface of the rear substrate 2 of the liquid crystal cell 1 .
- the optical axis direction of the first viewing angle compensating layer 20 is set to parallel with a direction substantially parallel to or substantially perpendicular to the aligning treatment direction of the first alignment film 7 formed on the rear substrate 2 .
- the second viewing angle compensating plate 22 is arranged so that a surface of the second viewing angle compensating layer 23 of this viewing angle compensating plate 22 where a tilt angle of the discotic liquid crystal molecules is large (a surface opposite to the base film 24 side) faces the outer surface of the front substrate 3 of the liquid crystal cell 1 . Additionally, the optical axis direction of the second viewing angle compensating layer 23 is set to parallel with a direction substantially parallel to or substantially perpendicular to the aligning treatment direction of the second alignment film 8 formed on the front substrate 3 .
- FIG. 8 shows aligning treatment directions 7 a and 8 a of the first and second alignment films 7 and 8 of the liquid crystal cell 1 , directions of absorption axes 12 a and 16 a of the polarizing layers 12 and 16 of the first and second polarizing plates 11 and 15 , and directions of optical axis directions 20 a and 23 a of the viewing angle compensating layers 20 and 23 of the first and second viewing angle compensating plates 19 and 22 .
- the first alignment film 7 formed on the rear substrate 2 of the liquid crystal cell 1 is aligned in a first direction crossing a lateral axis direction (a direction indicated by an alternate long and short dash line in the drawing) of a screen of the liquid crystal display device counterclockwise as seen from the observation side at an angle of substantially 45°.
- the second alignment film 8 formed on the front substrate 3 is aligned in a second direction (a direction crossing the lateral axis direction of the screen clockwise as seen from the observation side at an angle of substantially 45°) crossing the first direction at an angle of substantially 90°.
- the liquid crystal molecules 10 a in the liquid crystal layer 10 held between the first alignment film 7 of the rear substrate 2 and the second alignment film 8 of the front substrate 3 are twistaligned in a layer thickness direction of the liquid crystal layer 10 between the first alignment film 7 and the second alignment film 8 at a twisted angle of substantially 90° as indicated by an arrow of a dashed line that shows a twisted direction of a molecular orientation.
- a value of a retardation apparently varies in the range of substantially ⁇ /2 with respect to transmitted light in accordance with an alignment state of the liquid crystal molecules 10 a that changes in accordance with a voltage applied to the liquid crystal layer 10 between the electrodes 4 and 5 on the pair of substrates 2 and 3 .
- the first polarizing plate 11 facing the outer surface of the rear substrate 2 of the liquid crystal cell 1 is arranged so that the absorption axis 12 a of the first polarizing layer 12 of this polarizing plate 11 is set to parallel with a direction crossing the lateral axis direction of the screen clockwise as seen from the observation side at an angle of substantially 90°, i.e., crossing the aligning treatment direction 7 a of the first alignment film 7 of the rear substrate 2 clockwise as seen from the observation side at an angle of substantially 45°.
- the second polarizing plate 15 facing the outer surface of the front substrate 3 of the liquid crystal cell 1 is arranged so that the absorption axis 16 a of the second polarizing layer 16 of this polarizing plate 15 is set to parallel with a direction (a direction substantially parallel with the lateral axis direction of the screen) substantially perpendicular to the absorption axis 12 a of the polarizing layer 12 of the first polarizing plate 11 .
- the first viewing angle compensating plate 19 between the rear surface 2 of the liquid crystal cell 1 and the first polarizing plate 11 is arranged so that the optical axis direction 20 a of the first viewing angle compensating layer 20 of this viewing angle compensating plate 19 is set to parallel with a direction substantially parallel with the aligning treatment direction 7 a of the first alignment film 7 of the rear substrate 2 .
- the second viewing angle compensating plate 22 between the front substrate 3 of the liquid crystal cell 1 and the second polarizing plate 15 is arranged so that the optical axis direction 23 a of the second viewing angle compensating layer 23 of this viewing angle compensating plate 22 is set to parallel with a direction substantially parallel with the aligning treatment direction 8 a of the second alignment film 8 of the front substrate 3 , i.e., a direction substantially perpendicular to the optical axis direction 20 a of the viewing angle compensating layer 20 of the first viewing angle compensating plate 19 .
- This liquid crystal display device controls transmission of white illumination light emitted from a non-illustrated surface light source arranged on a rear side thereof (the opposite side of the observation side) by application of a voltage to the liquid crystal layer 10 between the electrodes 4 and 5 in accordance with each of the plurality of pixel portions, and irradiates light of three colors, i.e., red, green, and blue, colored by the color filters 6 R, 6 G, and 6 B of three colors, i.e., red, green, and blue, corresponding to the plurality of pixel portions to the observation side, thereby displaying a color image.
- three colors i.e., red, green, and blue
- FIG. 9 shows a relationship between the ratio of the liquid crystal layer thickness d R , d G , and d B of the pixel portions having the respective colors, i.e., red, green, and blue, and a display chromaticity when light is emitted from each of the pixel portions having the colors, i.e., red, green, and blue, to display a white color.
- this liquid crystal display device is of a normally white type where the first polarizing plate 11 and the second polarizing plate 15 are arranged so that the absorption axes 12 a and 16 a of the respective polarizing layers 12 and 16 become substantially perpendicular to each other.
- This liquid crystal display device displays white when no voltage is applied to the liquid crystal layer 10 between the electrodes 4 and 5 of each pixel portion, and displays black when a voltage that is sufficiently high for the substantially all liquid crystal molecules 10 a in the layer thickness direction of the liquid crystal layer 10 to rise to be aligned substantially perpendicularly with respect to the substrate surfaces (which will be referred to as a saturation voltage) is applied to the liquid crystal layer 10 between the electrodes 4 and 5 of each pixel portion.
- the liquid crystal cell 1 having the liquid crystal layer 10 in which the liquid crystal molecules 10 a are twist-aligned with a twisted angle of substantially 90° between the pair of substrates 2 and 3 , a behavior of the liquid crystal molecules 10 a in the liquid crystal layer 10 near the pair of substrates 2 and 3 is suppressed by an anchoring effect of the alignment films 7 and 8 .
- the saturation voltage is applied to the liquid crystal layer 10 between the electrodes 4 and 5 , the liquid crystal molecules 10 a near the pair of substrates 2 and 3 do not rise to be aligned, and an in-plane retardation (which will be referred to as a residual retardation) due to the liquid crystal molecules 10 a in the liquid crystal layer 10 near the substrates 2 and 3 is present.
- the liquid crystal layer 10 has a negative phase difference (which will be referred to as a phase difference in the liquid crystal layer thickness direction) in a plane perpendicular to the substrate surfaces.
- the phase difference in the liquid crystal layer thickness direction greatly functions with respect to light that obliquely enters the substrate surfaces, thereby reducing viewing angle characteristics.
- the first and second viewing angle compensating plates 19 and 22 are respectively arranged between the first and second polarizing plates 11 and 15 arranged on the front and the rear sides of the liquid crystal cell 1 and the rear substrate 2 and the front substrate 3 of the liquid crystal cell 1 so that the first and second viewing angle compensating plates 19 and 22 cancel out the residual retardation.
- the phase difference of the liquid crystal layer 10 in the plane perpendicular to the substrate surfaces when the saturation voltage (a voltage sufficiently high for the liquid crystal molecules 10 a to rise to be aligned) is applied to the liquid crystal layer 10 between the electrodes 4 and 5 of the liquid crystal cell 1 is canceled out by the phase differences of the plurality of optical layers within the plane perpendicular to the substrate surfaces.
- the plurality of optical layers include the base films 14 and 18 on the surfaces of the first and second polarizing plates 11 and 15 facing the liquid crystal cell 1 between the first polarizing layer 12 of the first polarizing plate 11 and the second polarizing layer 16 of the second polarizing plate 15 , the respective viewing angle compensating layers 20 and 23 of the first and second viewing angle compensating plates 19 and 22 , and the base films 21 and 24 of the first and second viewing angle compensating plates 19 and 22 .
- a value of a product of the phase difference of the liquid crystal layer 10 in the liquid crystal layer thickness direction and the liquid crystal layer thickness (an average value of the liquid crystal layer thicknesses d R , d G , and d B of the pixel portions having the respective colors to which the red, the green, and the blue color filters 6 R, 6 G, and 6 B are provided) d is determined as a retardation in the liquid crystal layer thickness direction, and a value of a product of the phase difference in the thickness direction of each of the plurality of optical layers and each layer thickness is determined as a retardation in the thickness direction.
- FIG. 10 shows a relationship between a product ⁇ nd of an anisotropic refractive index ⁇ n and the liquid crystal layer thickness d of a liquid crystal material constituting the liquid crystal layer 10 and a liquid crystal layer thickness direction retardation Rth LC of the liquid crystal layer 10 when the saturation voltage is applied on the assumption that a pre-tilt angle of the liquid crystal molecules 10 a is 5.5° and the saturation voltage is 4V.
- the liquid crystal layer thickness direction retardation Rth LC of the liquid crystal layer 10 when the saturation voltage is applied varies as shown in the drawing in accordance with a value of the product ⁇ nd of the liquid crystal layer 10 .
- the retardation Rth LC in the liquid crystal layer thickness direction linearly varies with respect to a change in a value of the product ⁇ n of the liquid crystal layer 10 .
- the retardation Rth LC is obtained by multiplying the value of the product ⁇ nd of the liquid crystal layer 10 by a coefficient corresponding to an inclination of the straight line depicted in FIG. 10 .
- the next Table 1 shows a relationship between the retardation Rth LC in the liquid crystal layer thickness direction of the liquid crystal layer 10 having the liquid crystal molecules 10 a with a pre-tilt angle and a saturation voltage being changed and a coefficient value that is multiplied with respect to a value ⁇ nd of the liquid crystal layer to calculate a value of the retardation in the thickness direction of each of the plurality of optical layers.
- a value of the retardation in the liquid crystal layer thickness direction of the liquid crystal layer 10 at the time of applying the saturation voltage is calculated by multiplying a coefficient falling within the range of 0.72 to 0.86 by a value of ⁇ nd of the liquid crystal layer.
- the value of the retardation in the liquid crystal thickness direction of the liquid crystal layer 10 at the time of applying the saturation voltage and a total value of the retardations in the thickness direction of the plurality of optical layers excluding the liquid crystal layer 10 have substantially the same absolute values, and have opposite signs.
- the total value of the retardations in the thickness direction of the plurality of optical layers between the first polarizing layer 12 and the second polarizing layer 16 excluding the liquid crystal layer 10 is set to a value obtained by multiplying the value of ⁇ nd of the liquid crystal layer 10 by a coefficient falling within the range of 0.72 to 0.86, and a total value of the values of the retardations in the thickness direction of the plurality of optical layers excluding the liquid crystal layer 10 and the retardation in the liquid crystal layer thickness direction of the liquid crystal layer 10 at the time of applying the saturation voltage is set to fall within the range of 0 ⁇ 80 nm ( ⁇ 80 nm to +80 nm).
- a value obtained by multiplying a coefficient 0.83 by the value of ⁇ nd of the liquid crystal layer 10 is set to a value obtained by multiplying the value of ⁇ nd of the liquid crystal layer 10 .
- FIG. 11 shows a transmittance of the liquid crystal display device with respect to a value Ro+ ⁇ nd that is obtained by adding an in-plane retardation Ro acquired by adding values of in-plane retardations of the plurality of optical layers excluding the liquid crystal layer 10 between the first polarizing layer 12 of the first polarizing plate 11 and the second polarizing layer of the second polarizing plate in the liquid crystal display device to the product ⁇ nd of the liquid crystal layer 10 .
- the plurality of optical layers include the base films 14 and 18 on the surfaces of the first and second polarizing plates 11 and 15 facing the liquid crystal cell 1 , the viewing angle compensating layers 20 and 23 of the first and second viewing angle compensating plates 19 and 22 , and the base films 21 and 24 of the first and second viewing angle compensating plates 19 and 22 .
- the liquid crystal display device demonstrates a high transmittance when a value of Ro+ ⁇ nd falls within the range of 350 nm to 600 nm, and a peak when a value of Ro+ ⁇ nd is 480 nm in particular.
- a value obtained by adding a total value of the in-plane retardations each of which is a product of an in-plane phase difference in a plane parallel to the substrate surfaces of each of the plurality of optical layers between the first polarizing layer 12 and the second polarizing layer 16 and a layer thickness of the optical layer to ⁇ nd of the liquid crystal layer 10 is set to the range of 350 nm to 600 nm, or preferably 480 nm.
- an optical function of the base films 13 and 17 placed outside the first and second polarizing layers 12 and 16 of the first and second polarizing plates 11 and 15 does not concern visibility of an observer.
- the plurality of optical layers between the first polarizing layer 12 and the second polarizing layer 16 concern visibility of the observer, the plurality of optical layers including the base films 14 and 18 of the first and second polarizing plates 11 and 15 , the first and second viewing angle compensating layers 20 and 23 of the first and second viewing angle compensating plates 19 and 22 , the base films 21 and 24 of these compensating layers 20 and 23 , and the liquid crystal layer 10 .
- FIG. 18 showing X, Y, and Z coordinates of an optical medium 100 and refractive indices in respective coordinate axis directions
- a thickness direction perpendicular to the substrate surfaces is a Z axis
- a refractive index in the X axis direction is nx
- a refractive index in the Y axis direction is ny
- a refractive index in the Z axis direction is nz
- a layer thickness of the optical layer is d
- a retardation Rthi in the thickness direction of each optical layer is expressed as ⁇ (nx+ny)/2 ⁇ nz ⁇ d.
- the total retardation Rth in the thickness direction is set to fall within the range satisfying the following expression:
- Rth 0.83 ⁇ nd ⁇ 80 nm.
- the total retardation Rth in the thickness direction is set to fall within the range of 0.83 ⁇ nd ⁇ 80 nm to 0.83 ⁇ nd+80 nm.
- the totalized in-plane retardation Ro is set to the range satisfying the following expression:
- Ro+ ⁇ nd 350 nm to 600 nm.
- the retardation Rth in the thickness direction obtained by adding values of the retardations Rthi in the thickness direction, which is expressed as ⁇ (nx+ny)/2 ⁇ nz ⁇ d, of the plurality of the optical layers between the first polarizing layer 12 and the second polarizing layer 16 excluding the liquid crystal layer 10 is 353 nm
- the in-plane retardation Ro obtained by adding values of the in-plane retardations Roi of the plurality of optical layers is 12 nm.
- the value 0.83 ⁇ nd obtained by multiplying the value of ⁇ nd of the liquid crystal layer 10 by the preferable coefficient 0.83 is 315 nm
- the value 353 nm as the added retardation Rth in the thickness direction falls within the range of a value obtained by adding 80 nm to ⁇ 315 nm or +315 nm as a value of 0.83 ⁇ nd.
- the value obtained by totalizing the added in-plane retardation Ro and ⁇ nd is 392 nm, and falls within the range of 350 nm to 600 nm that defines the range of Ro+ ⁇ nd.
- this liquid crystal display device has the above-explained structure, angle dependency of the transmittance is improved, and a display wide viewing angle is increased. Further, in the television receiver using this liquid crystal display device, its viewing angle is increased.
- FIGS. 12A to 12D are viewing angle characteristic views at the time of white display T W , black display T B , 50% gradation (a gradation with 50% brightness of white display) display T 50 , and 20% gradation (a gradation with 20% brightness of white display) display T 20 of the liquid crystal display device.
- FIG. 12A shows viewing angle characteristics in a right-and-left direction of the screen
- FIG. 12B shows viewing angle characteristics in an up-and-down direction of the screen
- FIG. 12C shows viewing angle characteristics in a direction from a lower left side to a lower right side of the screen
- FIG. 12D shows viewing angle characteristics in a direction from a lower right side to an upper left side of the screen.
- a negative angle is an angle in the left direction and a positive angle is an angle in the right direction in FIG. 12A .
- a negative angle is an angle in the lower direction
- a positive angle is an angle in the upper direction.
- a negative angle is an angle in the lower left direction and a positive angle is an angle in the upper right direction.
- a negative angle is an angle in the lower right direction and a positive angle is an angle in the upper left direction.
- the liquid crystal display device has the viewing angle characteristics that the angle dependency of a transmittance in each direction, i.e., the right-and-left direction, the up-and-down direction, the direction from the lower left to the lower right, and the direction from the lower right to the upper left in the screen is improved, i.e., inversion of the intermediate gradation does not occur in a wide angle range in each of these directions.
- the television receiver using this liquid crystal display device has wide viewing angles in a right-and-left direction, a direction from the lower left to the lower right, and a direction from the lower right to the upper left in particular.
- a value of ⁇ nd of the liquid crystal layer 10 in the liquid crystal cell 1 is set to 380 nm in the liquid crystal display device, but the value of ⁇ nd of the liquid crystal layer 10 may be set to any other value.
- FIGS. 13A to 13D are viewing angle characteristic views at the time of white display T W , black display T B , 50% gradation display T 50 , and 20% gradation display T 20 in a liquid crystal display device in which a value of ⁇ nd of the liquid crystal layer 10 is set to 505 nm and the other structures are the same as those in the foregoing embodiment.
- FIG. 13A shows viewing angle characteristics in the right-and-left direction of the screen
- FIG. 13B shows viewing angle characteristics in the up-and-down direction of the screen
- FIG. 13C shows viewing angle characteristics in the direction from the lower left to the lower right of the screen
- FIG. 13D shows viewing angle characteristics in the direction from the lower right to the upper left of the screen.
- the liquid crystal display device has viewing angle characteristics that angle dependency of a transmittance in each direction, i.e., the right-and-left direction, the up-and-down direction, the direction from the lower left to the lower right, and the direction from the lower right to the upper left in the screen is improved and inversion of the intermediate gradation does not occur in a wide angle range in each of these directions. Moreover, contrast is higher than that of the liquid crystal display device according to the foregoing embodiment.
- FIGS. 14 to 16 show a second embodiment according to the present invention
- FIG. 14 is a schematic cross-sectional view of a liquid crystal display device used in the second embodiment.
- the liquid crystal display device has a structure where a first retardation plate 26 is arranged between the first polarizing plate 11 and the first viewing angle compensating plate 19 and a second retardation plate 27 is arranged between the second polarizing plate 15 and the second viewing angle compensating plate 22 in the liquid crystal display device according to the first embodiment.
- a plurality of optical layers between a first polarizing layer 12 and a second polarizing layer 16 excluding a liquid crystal layer 10 include base films 14 and 18 on surfaces of the first and second polarizing layers 12 and 16 facing a liquid crystal cell 1 , the first and second viewing angle compensating layers 20 and 23 , base films 21 and 24 of these compensating layers 20 and 23 , and the first and second retardation plates 26 and 27 . It is to be noted that other structures of the liquid crystal display device according to this embodiment are substantially the same as those in the first embodiment.
- FIG. 15 shows aligning treatment directions 7 a and 8 a of first and second alignment films 7 and 8 of the liquid crystal cell 1 , directions of absorption axes 12 a and 16 a of the polarizing layers 12 and 16 of the first and second polarizing plates 11 and 15 , optical axis directions 20 a and 23 a of the viewing angle compensating layers 20 and 23 of the first and second viewing angle compensating plates 19 and 22 , and directions of retardation axes 26 a and 27 a of the first and second retardation plates 26 and 27 in the liquid crystal display device according to this embodiment.
- the aligning treatment directions 7 a and 8 a of the first and second alignment films 7 and 8 of the liquid crystal cell 1 , the directions of the absorption axes 12 a and 16 a of the polarizing layers 12 and 16 of the first and second polarizing plates 11 and 15 , and the optical axis directions 20 a and 23 a of the viewing angle compensating layers 20 and 23 of the first and second viewing angle compensating plates 19 and 22 are the same as those in the first embodiment.
- the first retardation plate 26 is arranged so that its retardation axis 26 a is set to parallel with a direction substantially parallel with the optical axis direction 20 a of the first viewing angle compensating layer 20 of the first viewing angle compensating plate 19 .
- the second retardation plate 27 is arranged so that its retardation axis 27 a is set to parallel with a direction substantially parallel with the optical axis direction 23 a of the second viewing angle compensating layer 23 of the second viewing angle compensating plate 22 .
- a total value of the retardation value in the thickness direction of each of the plurality of optical layers between the first polarizing layer 12 and the second polarizing layer 16 excluding the liquid crystal layer 10 and the retardation value in the liquid crystal layer direction of the liquid crystal layer 10 at the time of applying a voltage is set to the range of ⁇ 80 nm to +80 nm.
- FIGS. 16A to 16D are viewing angle characteristic views at the time of white display T W , black display T B , 50% gradation display T 50 , and 20% gradation display T 20 of the liquid crystal display device according to this embodiment.
- FIG. 16A shows viewing angle characteristics in a right-and-left direction of a screen
- FIG. 16B shows viewing angle characteristics in an up-and-down direction of the screen
- FIG. 16C shows viewing angle characteristics in a direction from the lower left to the lower right of the screen
- FIG. 16D shows viewing angle characteristics in a direction from the lower right to the upper left of the screen.
- this liquid crystal display device has viewing angle characteristics that inversion of the intermediate gradation does not occur in a wide angle range in each of these directions, and a viewing angle is wide and contrast is high in the right-and-left direction, the direction from the lower left to the lower right, and the direction from the lower right to the upper left.
- FIGS. 17 , 19 , and 20 show a third embodiment according to the present invention
- FIG. 17 is a schematic cross-sectional view of a liquid crystal display device used in the third embodiment.
- the liquid crystal display device has a structure where first and second optical films 28 and 29 having a phase difference are further arranged between the first retardation plate 26 and the first viewing angle compensating plate 19 and between the second retardation plate 27 and the second viewing angle compensating plate 22 in the liquid crystal display device according to the second embodiment.
- a plurality of optical layers between a first polarizing layer 12 and a second polarizing layer 16 excluding a liquid crystal layer 10 include base films 14 and 18 on surfaces of the first and second polarizing layers 12 and 16 facing a pair of substrates 2 and 3 of a liquid crystal cell 1 , the first and second viewing angle compensating layers 20 and 23 and their base films 21 and 24 , the first and second retardation plates 26 and 27 , and the first and second optical films 28 and 29 . It is to be noted that other structures of the liquid crystal display device according to this embodiment are substantially the same as those of the second embodiment.
- each of the first and second optical films 28 and 29 is a retardation film having an optical axis in the thickness direction z perpendicular to the film surface.
- FIG. 19 shows aligning treatment directions 7 a and 8 a of the first and second alignment films 7 and 8 of the liquid crystal cell 1 , directions of absorption axes 12 a and 16 a of the polarizing layers 12 and 16 of the first and second polarizing plates 11 and 15 , optical axis directions 20 a and 23 a of the viewing angle compensating layers 20 and 23 of the first and second viewing angle compensating plates 19 and 22 , directions of retardation axes 26 a and 27 a of the first and second retardation plates 26 and 27 , and directions of optical axes 28 a and 29 a of the first and second optical films 28 and 29 .
- the aligning treatment directions 7 a and 8 a of the first and second alignment films 7 and 8 of the liquid crystal cell 1 , the directions of the absorption axes 12 a and 16 a of the polarizing layers 12 and 16 of the first and second polarizing plates 11 and 15 , and the optical axis directions 20 a and 23 a of the viewing angle compensating layers 20 and 23 of the first and second viewing angle compensating plates 19 and 22 are the same as those in the first and second embodiments.
- the first retardation plate 26 is arranged so that its retardation axis 26 a is set to parallel with a direction crossing a lateral axis direction (a direction indicated by an alternate long and shot dash line in the drawing) of the screen counterclockwise as seen from an observation side at an angle of substantially 110°.
- the second retardation plate 27 is arranged so that its retardation axis 27 a is set to parallel with a direction crossing the lateral axis direction of the screen clockwise as seen from the observation side at an angle of substantially 20°, i.e., a direction substantially perpendicular to the retardation axis 26 a of the first retardation plate 26 .
- the directions of the optical axes 28 a and 29 a of the first and second optical films 28 and 29 are perpendicular to the substrate surfaces of the liquid crystal cell 1 .
- a total value of the values of the retardations in the thickness direction of the plurality of optical layers between the first polarizing layer 12 and the second polarizing layer 16 excluding the liquid crystal layer 10 and the value of the retardation in the liquid crystal layer thickness direction of the liquid crystal layer 10 is set to the range of 0 ⁇ 80 nm.
- FIGS. 20A to 20D are viewing angle characteristic views at the time of white display T W , black display T B , 50% gradation display T 50 , and 20% gradation display T 20 of the liquid crystal display device according to this embodiment.
- FIG. 20A shows viewing angle characteristics in a right-and-left direction of a screen
- FIG. 20B shows viewing angle characteristics in an up-and-down direction of the screen
- FIG. 20C shows viewing angle characteristics in a direction from the lower left to the lower right of the screen
- FIG. 20D shows viewing angle characteristics in a direction from the lower right to the upper left of the screen.
- the liquid crystal display device has viewing angle characteristics that angle dependency of a transmittance in each direction, i.e., the right-and-left direction, the up-and-down direction, the direction from the lower left to the lower right, and the direction from the lower right to the upper left in the screen is improved and inversion of the intermediate gradation does not occur in a wide angle range in each of the these directions.
- the television receiver using this liquid crystal display device has wide viewing angles in a right-and-left direction, a direction from the lower left to the lower right, and a direction from the lower right to the upper left and also has high contrast in particular.
- FIGS. 21 to 23 show a fourth embodiment according to the present invention
- FIG. 21 is a schematic cross-sectional view of a liquid crystal display device used in the fourth embodiment.
- the liquid crystal display device has a structure where the optical film 29 provided in the third embodiment is further arranged either between the first retardation plate 26 and the first viewing angle compensating plate 19 or between the second retardation plate 27 and the second viewing angle compensating plate 22 , e.g., between the first retardation plate 26 and the first viewing angle compensating plate 19 in the liquid crystal display device according to the second embodiment.
- a plurality of optical layers between a first polarizing layer 12 and a second polarizing layer 16 excluding a liquid crystal layer 10 include base films 14 and 18 on surfaces of the first and second polarizing layers 12 and 16 facing a pair of substrates 2 and 3 of a liquid crystal cell 1 , the first and second viewing angle compensating layers 20 and 23 and their base films 21 and 24 , the first and second retardation plates 26 and 27 , and the optical film 29 . It is to be noted that other structures of the liquid crystal display device according to this embodiment are substantially the same as those according to the third embodiment.
- FIG. 22 show aligning treatment directions 7 a and 8 a of first and second alignment films 7 and 8 of the liquid crystal cell 1 , directions of absorption axes 12 a and 16 a of the polarizing layers 12 and 16 of the first and second polarizing plates 11 and 15 , optical axis directions 20 a and 23 a of the viewing angle compensating layers 20 and 23 of the first and second viewing angle compensating plates 19 and 22 , directions of retardation axes 26 a and 27 a of the first and second retardation plates 26 and 27 , and a direction of an optical axis 29 a of the optical film 29 .
- the aligning treatment directions 7 a and 8 a of the first and second alignment films 7 and 8 of the liquid crystal cell 1 , the directions of the absorption axes 12 a and 16 a of the polarizing layers 12 and 16 of the first and second polarizing plates 11 and 15 , and the optical axis directions 20 a and 23 a of the viewing angle compensating layers 20 and 23 of the first and second viewing angle compensating plates 19 and 22 are the same as those in the second embodiment.
- the direction of the retardation axis 26 a of the first retardation plate 26 , the direction of the retardation axis 27 a of the second retardation plate 27 are the same as those in the third embodiment.
- the direction of the optical axis 29 a of the optical film 29 is perpendicular to substrate surfaces of the liquid crystal cell 1 .
- FIGS. 23A to 23D are viewing angle characteristic views at the time of white display T W , black display T B , 50% gradation display T 50 , and 20% gradation display T 20 of the liquid crystal display device according to this embodiment.
- FIG. 23A shows viewing angle characteristics in a right-and-left direction of a screen
- FIG. 23B shows viewing angle characteristics in an up-and-down direction of the screen
- FIG. 23C shows viewing angle characteristics in a direction from the lower left to the lower right
- FIG. 23D shows viewing angle characteristics in a direction from the lower right to the upper left.
- the liquid crystal display device has viewing angle characteristics that angle dependency of a transmittance in each direction, i.e., the right-and-left direction, the up-and-down direction, the direction from the lower left to the lower right, and the direction from the lower right to the upper left is improved and inversion of an intermediate gradation does not occur in a wide angle range in each of the these direction.
- the television receiver using this liquid crystal display device has wide viewing angles in a right-and-left direction, a direction from the lower left to the lower right, and a direction from the lower right to the upper left and also has high contrast in particular.
- FIGS. 24 to 26 show a fifth embodiment according to the present invention
- FIG. 24 is a schematic cross-sectional view of a liquid crystal display device used in the fifth embodiment.
- the liquid crystal display device has a structure where first and second viewing angle compensating layers 20 and 23 are formed on plate surfaces of first and second retardation plates 26 and 27 in the liquid crystal display device according to the second embodiment.
- a plurality of optical layers between a first polarizing layer 12 and a second polarizing layer 16 excluding a liquid crystal layer 10 include base films 14 and 16 on surfaces of the first and second polarizing layers 12 and 16 facing a pair of substrates 2 and 3 of a liquid crystal cell 1 , the first and second viewing angle compensating layers 20 and 23 , and the first and second retardation plates 26 and 27 . It is to be noted that other structures of the liquid crystal display device according to this embodiment are substantially the same as those in the second embodiment.
- FIG. 25 shows aligning treatment directions 7 a and 8 a of first and second alignment films 7 and 8 of the liquid crystal cell 1 , directions of absorption axes 12 a and 16 a of the polarizing layers 12 and 16 of first and second polarizing plates 11 and 15 , optical axis directions 20 a and 23 a of the first and second viewing angle compensating layers 20 and 23 , and directions of retardation axes 26 a and 27 a of the first and second retardation plates 26 and 27 in the liquid crystal display device according to the present invention.
- the aligning treatment directions 7 a and 8 a of the first and second alignment films 7 and 8 of the liquid crystal cell 1 , the directions of the absorption axes 12 a and 16 a of the polarizing layers 12 and 16 of the first and second polarizing plates 11 and 15 , and the optical axis directions 20 a and 23 a of the first and second viewing angle compensating layers 20 and 23 are the same as those in the first embodiment. Furthermore, the direction of the retardation axis 26 a of the first retardation plate 26 and the direction of the retardation axis 27 a of the second retardation plate 27 are the same as those in the third embodiment.
- a total value of the retardation values in the thickness direction of the plurality of optical layers between the first polarizing layer 12 and the second polarizing layer 16 excluding the liquid crystal layer 10 and a retardation value in a liquid crystal layer thickness direction of the liquid crystal layer 10 is set to fall within the range of 0 ⁇ 80 nm.
- the base films 14 and 18 alone on the surfaces of the first and second polarizing layers 12 and 16 facing the liquid crystal cell 1 are determined as the base films having the retardations in the thickness direction among the plurality of optical layers between the first polarizing layer 12 and the second polarizing layer 16 . Since the number of the base films having the retardations in the thickness direction is reduced in this manner, the angle dependency of a transmittance is further efficiently improved.
- FIGS. 26A to 26D are viewing angle characteristic views at the time of white display T W , black display T B , 50% gradation display T 50 , and 20% gradation display T 20 of the liquid crystal display device according to this embodiment.
- FIG. 26A shows viewing angle characteristics in a right-and-left direction of a screen
- FIG. 26B shows viewing angle characteristics in an up-and-down direction of the screen
- FIG. 26C shows viewing angle characteristics in a direction from the lower left to the lower right of the screen
- FIG. 26D shows viewing angle characteristics of a direction from the lower right to the upper left of the screen.
- the liquid crystal display device has viewing angle characteristics that angle dependency of a transmittance in each direction, i.e., the right-and-left direction, the up-and-down direction, the direction from the lower left to the lower right, and the direction from the lower right to the upper left and inversion of an intermediate gradation does not occur in a wide angle range in each of these directions.
- the television receiver using this liquid crystal display device has wide viewing angles in a right-and-left direction, a direction from the lower left to the lower right, and a direction from the lower right to the upper left and also has high contrast in particular.
- FIGS. 27 to 29 show a sixth embodiment according to the present invention
- FIG. 27 is a schematic cross-sectional view of a liquid crystal display device used in the sixth embodiment.
- the liquid crystal display device has a structure where base films 13 and 17 are provided on outer surfaces alone of first and second polarizing layers 12 and 16 opposite to surfaces of the same facing a pair of substrates 2 and 3 of a liquid crystal cell 1 and first and second retardation plates 26 and 27 are respectively laminated on the surfaces of the first and second polarizing layers 12 and 16 facing the liquid crystal cell 1 .
- a plurality of optical layers between the first polarizing layer 12 and the second polarizing layer 16 excluding a liquid crystal layer 10 include the first and second retardation plates 26 and 27 , the first and second viewing angle compensating layers 20 and 23 , and base films 21 and 24 of these viewing angle compensating layers 20 and 23 . It is to be noted that other structures of the liquid crystal display device according to this embodiment are substantially the same as those in the second embodiment.
- FIG. 28 shows aligning treatment directions 7 a and 8 a of first and second alignment films 7 and 8 of the liquid crystal cell 1 , directions of absorption axes 12 a and 16 a of the first and second polarizing layers 12 and 16 , optical axis directions 20 a and 23 a of the first and second viewing angle compensating layers 20 and 23 , and directions of retardation axes 26 a and 27 a of the first and second retardation plates 26 and 27 in the liquid crystal display device according to this embodiment.
- the aligning treatment directions 7 a and 8 a of the first and second alignment films 7 and 8 of the liquid crystal cell 1 the directions of the absorption axes 12 a and 16 a of the first and second polarizing layers 12 and 16 , the optical axis directions 20 a and 23 a of the first and second viewing angle compensating layers 20 and 23 , and the directions of the retardation axes 26 a and 27 a of the first and second retardation plates 26 and 27 are the same as those in the first embodiment.
- a value of ⁇ nd of a liquid crystal layer 10 of the liquid crystal cell 1 is set to 420 nm
- a total value of the retardation values in the thickness direction of the plurality of optical layers between the first polarizing layer 12 and the second polarizing layer 16 excluding the liquid crystal layer 10 and a retardation value in a liquid crystal layer thickness direction of the liquid crystal layer 10 is set to fall within the range of 0 ⁇ 80 nm in this manner.
- the base films 13 and 17 are provided on the outer surfaces alone of the first and second polarizing layers 12 and 16 , and the first and second retardation plates 26 and 27 are laminated on the surfaces of the first and second polarizing layers 12 and 16 facing the liquid crystal cell 1 .
- the base films 21 and 24 of the first and second viewing angle compensating layers 20 and 23 alone are determined as the base films having the retardations in the thickness direction among the plurality of optical layers between the first polarizing layer 12 and the second polarizing layer 16 . Since the number of base films having the retardations in the thickness direction is reduced in this manner, the angle dependency of a transmittance is further effectively improved.
- FIGS. 29A to 29D are viewing angle characteristic views at the time of white display T W , black display T B , 50% gradation display T 50 , and 20% gradation display T 20 of a liquid crystal display device according to this embodiment.
- FIG. 29A shows viewing angle characteristics in a right-and-left direction of a screen
- FIG. 29B shows viewing angle characteristics in an up-and-down direction of the screen
- FIG. 29C shows viewing angle characteristics of a direction from the lower left to the lower right of the screen
- FIG. 29D shows viewing angle characteristics in a direction from the lower right to the upper left of the screen.
- the liquid crystal display device has viewing angle characteristics that the angle dependency of a transmittance in each direction, i.e., the right-and-left direction, the up-and-down direction, the direction from the lower left to the lower right, and the direction from the lower right to the upper left of the screen is improved and inversion of an intermediate gradation does not occur in a wide angle range in each of these directions.
- the television receiver using this liquid crystal display device has wide viewing angles in a right-and-left direction, a direction from the lower left to the lower right, and a direction from the lower right to the upper left and also has high contrast in particular.
- FIGS. 30 to 32 show a seventh embodiment according to the present invention
- FIG. 30 is a schematic cross-sectional view of a liquid crystal display device used in the seventh embodiment.
- the liquid crystal display device has a structure where base films 13 and 17 are provided on outer surfaces alone of first and second polarizing layers 12 and 16 opposite to surfaces of the same facing a pair of substrates 2 and 3 of a liquid crystal cell 1 , first and second retardation plates 26 and 27 are laminated on the surfaces of the first and second polarizing layers 12 and 16 facing the liquid crystal cell 1 , and first and second viewing angle compensating layers 20 and 23 are formed on surfaces of the first and second retardation plates 26 and 27 facing the liquid crystal cell 1 in the liquid crystal display device according to the second embodiment.
- a plurality of optical layers between the first polarizing layer 12 and the second polarizing layer 16 excluding a liquid crystal layer 10 include the first and second retardation plates 26 and 27 and the first and second viewing angle compensating layers 20 and 23 . It is to be noted that other structures of the liquid crystal display device according to this embodiment are substantially the same as those in the second embodiment.
- FIG. 31 shows aligning treatment directions 7 a and 8 a of first and second alignment films 7 and 8 of the liquid crystal cell 1 , directions of absorption axes 12 a and 16 a of the first and second polarizing layers 12 and 16 , optical axis directions 20 a and 23 a of the first and second viewing angle compensating layers 20 and 23 , and directions of retardation axes 26 a and 27 a of the first and second retardation plates 26 and 27 in the liquid crystal display device according to this embodiment.
- the aligning treatment directions 7 a and 8 a of the first and second alignment films 7 and 8 of the liquid crystal cell 1 , the directions of the absorption axes 12 a and 16 a of the first and second polarizing layers 12 and 16 , and the optical axis directions 20 a and 23 a of the first and second viewing angle compensating layers 20 and 23 are the same as those in the first embodiment.
- the first retardation plate 26 is arranged so that its retardation axis 26 a is set to parallel with a direction crossing a lateral axis direction of the screen counterclockwise as seen from an observation side at an angle of substantially 100°.
- the second retardation plate 27 is arranged so that its retardation axis 27 a is set to parallel with a direction crossing the lateral axis direction of the screen counterclockwise as seen from the observation side at an angle of substantially 10°, i.e., a direction substantially perpendicular to the retardation axis 26 a of the first retardation plate 26 .
- a total value of the retardation values in the thickness direction of the plurality of optical layers between the first polarizing layer 12 and the second polarizing layer 16 excluding the liquid crystal layer 10 and a retardation value in a liquid crystal layer thickness direction of the liquid crystal layer 10 is set to fall within the range of 0 ⁇ 80 nm.
- the base films 13 and 17 are provided on the outer surfaces alone of the first and second polarizing layers 12 and 16 opposite to the surfaces facing the pair of substrates 2 and 3 of the liquid crystal cell 1 , the first and second retardation plates 26 and 27 are laminated on the surfaces of the first and second polarizing layers 12 and 16 facing the liquid crystal cell 1 , and the first and second viewing angle compensating layers 20 and 23 are formed on the surfaces of the first and second retardation plates 26 and 27 facing the liquid crystal cell 1 .
- base films having retardations in the thickness direction are eliminated from the plurality of optical layers between the first polarizing layer 12 and the second polarizing layer 16 , and the base films 21 and 24 alone of the first and second viewing angle compensating layers 20 and 23 are adopted.
- the angle dependency of a transmittance is further effectively improved.
- FIGS. 32A to 32D are viewing angle characteristic views at the time of white display T W , black display T B , 50% gradation display T 50 , and 20% gradation display T 20 of the liquid crystal display device according to this embodiment.
- FIG. 32A shows viewing angle characteristics in a right-and-left direction of a screen
- FIG. 32B shows viewing angle characteristics in an up-and-down direction of the screen
- FIG. 32C shows viewing angle characteristics in a direction from the lower left to the lower right of the screen
- FIG. 32D shows viewing angle characteristics in a direction from the lower right to the upper left of the screen.
- the liquid crystal display device has viewing angle characteristics that the angle dependency of a transmittance in each direction, i.e., the right-and-left direction, the up-and-down direction, the direction from the lower left to the lower right, and the direction from the lower right to the upper left of the screen is improved and inversion of the intermediate gradation does not occur in a wide angle range in each of these directions.
- the television receiver using this liquid crystal display device has wide viewing angles in a right-and-left direction, a direction from the lower left to the lower right, and a direction from the lower right to the upper left and also has high contrast in particular.
- each of the first and second viewing angle compensating layers 20 and 23 is formed of discotic liquid crystal layer in when discotic liquid crystal molecules 25 are hybrid-aligned
- the first and second viewing angle compensating layers are not restricted to the discotic liquid crystal layer, and it may be formed of a liquid crystal layer in which, e.g., elongated spherical liquid crystal molecules are inclined and aligned in one direction with respect to a plane parallel to the substrate surfaces of the liquid crystal cell 1 .
- the liquid crystal display device is of a normally white type in which the first polarizing layer 12 and the second polarizing layer 16 are arranged so that their absorption axes 12 a and 16 a are substantially perpendicular to each other
- the liquid crystal display device may be of a normally black type in which the first polarizing layer 12 and the second polarizing layer 16 are arranged so that their absorption axes 12 a and 16 a are substantially parallel to each other.
- the television receiver according to each of the foregoing embodiments is a digital broadcasting receiving apparatus that receives digital broadcast waves, demodulates the digital broadcast waves to output a transport stream, separates a picture signal and an audio signal from this transport stream, and decodes these separated signals to generate picture data and audio data
- the receiving apparatus according to the present invention may be an analog broadcast wave receiving apparatus that receives and demodulates analog broadcast waves, and separates a picture signal and an audio signal from an analog signal having various kinds of signals superimposed thereon to generate the picture signal and the audio signal in accordance with an STNC scheme.
- the television receiver using the liquid crystal display device has wide viewing angles.
- the liquid crystal display apparatus includes a liquid crystal display device.
- the liquid crystal display device includes: a liquid crystal cell including a pair of substrates in which at least one electrode and an alignment film covering the electrode are provided on each of inner surfaces of the substrates facing each other, and a liquid crystal layer that is sandwiched between the substrates and includes liquid crystal molecules twist-aligned; first and second polarizing plates that are arranged on both sides of the liquid crystal cell, each of the polarizing plates including a polarizing layer having a transmission axis allowing transmission of linear polarized light and an absorption axis in a direction perpendicular to the transmission axis, and at least one base film to support the polarizing layer; and first and second viewing angle compensating layers that are respectively arranged between the liquid crystal cell and the first and second polarizing plates, each of the viewing angle compensating layers having a phase difference within a plane parallel to substrate surfaces of the liquid crystal cell and a phase difference within a plane perpendicular to the substrate surfaces.
- a total value of retardations in a thickness direction each of which is a product of a phase difference within a plane perpendicular to the substrate surfaces and a layer thickness, of a plurality of optical layers between the first and second polarizing layers, including at least the first and second viewing angle compensating layers but excluding the liquid crystal layer, is set to a value that cancels out a retardation in a liquid crystal layer thickness direction, which is a product of a phase difference within a plane perpendicular to the substrate surfaces and a liquid crystal layer thickness, of the liquid crystal layer when a voltage sufficiently high to raise and align the liquid crystal molecules with respect to the substrate surfaces is applied to the liquid crystal layer between the electrodes of the first and second substrates.
- the liquid crystal display apparatus further includes a display driving section to supply signals to electrodes formed on a pair of substrates and to drive the liquid crystal display device based on picture data supplied from the outside.
- one of the pair of substrates is provided with at least one opposed electrode
- the other of the pair of substrates is provided with a plurality of pixel electrodes in which regions respectively facing the opposed electrode form a plurality of pixels aligned in a matrix to form images
- the display driving section includes: a scan line driving circuit to supply a scan signal that scans lines at least one by one to the plurality of pixels aligned in the matrix; a data line driving circuit to generate a signal supplied to each of the pixels in accordance with supplied picture data and supply the generated signal to each of the pixels; and a driving control circuit to control operations of the scan line driving circuit and the data line driving circuit.
- the retardation in the thickness direction of each of the plurality of optical layers and the retardation in the liquid crystal layer thickness direction of the liquid crystal layer to be set so that a value obtained by adding a total value of the retardations in the thickness direction of the plurality of optical layers and the value of the retardation in the liquid crystal layer thickness direction of the liquid crystal layer falls within the range of ⁇ 80 nm to +80 nm.
- the value of the retardation in the liquid crystal layer thickness direction of the liquid crystal layer when a voltage that is sufficiently high to raise and align the liquid crystal molecules is applied and the total value of the retardations in the thickness direction of the plurality of optical layers between the first and second polarizing layers excluding the liquid crystal layer to be set so that a difference between absolute values of these values is not greater than 80 nm and these values have a positive and a negative signs opposite to each other.
- the retardation in the liquid crystal layer thickness direction is a value calculated by multiplying a value of a product ⁇ nd of an anisotropic refractive index ⁇ n of a liquid crystal material constituting the liquid crystal layer and a liquid crystal layer thickness d by a coefficient in the range of 0.72 to 0.89 that is selected in accordance with a pre-tilt angle of the liquid crystal molecules with respect to the substrate surfaces and a value of the voltage that is sufficiently high to raise and align the liquid crystal molecules.
- each of the plurality of optical layers excluding the liquid crystal layer between the first polarizing layer and the second polarizing layer assuming that one and the other of two directions perpendicular to each other within a plane parallel to the substrate surfaces are an X axis and a Y axis, a thickness direction perpendicular to the substrate surfaces is a Z axis, a refractive index in the X axis direction is nx, a refractive index in the Y axis direction is ny, a refractive index in the Z axis direction is nz, and a layer thickness of the optical layer is d, it is preferable for a total value of retardations in the thickness direction of the respective optical layer each of which is expressed as ⁇ (nx+ny)/2 ⁇ nz ⁇ d to be set to a value that is substantially equal to a value calculated by multiplying a value of the product ⁇ nd of the anisotropic refractive index ⁇ n of the liquid crystal material constitu
- the total value of the retardation values in the thickness direction of the respective optical layers between the first and second polarizing layers excluding the liquid crystal layer prefferably be set substantially equal to a value calculated by multiplying the product ⁇ nd of the anisotropic refractive index ⁇ n of the liquid crystal material constituting the liquid crystal layer and the liquid crystal layer thickness d by a coefficient 0.83.
- a total value of in-plane retardations of the respective optical layers between the first and second polarizing layers including the liquid crystal layer prefferably be set to the range of 350 nm to 600 nm, the in-plane retardation of each optical layer being a product of an in-plane phase difference within a plane parallel to the substrate surfaces and a layer thickness of each optical layer.
- the liquid crystal cell includes: a first substrate having, on one surface thereof, at least one first electrode and a first alignment film covering the first electrode and subjected to an aligning treatment in a predetermined first direction; a second substrate that is arranged to face an electrode formation surface of the first substrate, and has, on a surface facing the first substrate, at least one second electrode facing the first electrode and a second alignment film covering the second electrode and subjected to an aligning treatment in a second direction crossing the first direction at an angle of substantially 90°; and a liquid crystal layer that is twist-aligned and held at a twisted angle of substantially 90° between the first alignment film of the first substrate and the second alignment film of the second substrate.
- the first polarizing plate has a first polarizing layer to have an absorption axis in a direction crossing an aligning treatment direction of the first alignment film at an angle of substantially 45°, and for the second polarizing plate to have a second polarizing layer having an absorption axis in a direction substantially perpendicular to or substantially parallel to the absorption axis of the first polarizing layer.
- each of the first and second polarizing layers preferably includes a base film formed of a resin film that is provided on at least a surface of the polarizing layer facing the first or second substrate and has a retardation in a thickness direction, which is a product of a phase difference within a plane perpendicular to the substrate surfaces and a layer thickness.
- Each of the first and second viewing angle compensating layers preferably includes a base film formed of a resin film that is provided on at least one surface of the viewing angle compensating layer and has a retardation in the thickness direction, which is a product of a phase difference within a plane perpendicular to the substrate surfaces and a layer thickness.
- the plurality of optical layers between the first and second polarizing layers excluding the liquid crystal layer preferably include at least the base films on the surfaces of the first and second polarizing layers facing the first and second substrates, the first and second viewing angle compensating layers, and the base films of these viewing angle compensating layers.
- each of the first and second polarizing layers preferably includes a base film formed of a resin film that is provided on at least the surface of the polarizing layer facing the first or second substrate and has a retardation in the thickness direction, which is a product of a phase difference within a plane perpendicular to the substrate surfaces and a layer thickness, and the first and second viewing angle compensating layers are preferably respectively formed on plate surfaces of the first retardation plate and the second retardation plate.
- each of the first and second polarizing layers preferably includes a base film formed of a resin film arranged on an outer surface of the polarizing layer opposite to the surface facing the first or second substrate.
- Each of the first and second viewing angle compensating layers preferably includes a base film formed of a resin film that is provided on at least one surface of the viewing angle compensating layer and has a retardation in the thickness direction, which is a product of a phase difference in a plane perpendicular to the substrate surfaces and a layer thickness.
- the first and second retardation plates are preferably laminated on the surfaces of the first and second polarizing layers facing the first and second substrates, respectively.
- each of the first and second polarizing layers preferably includes a base film formed of a resin film arranged on the outer surface of the polarizing layer opposite to the surface facing the first or second substrate.
- the first and second retardation plates are preferably laminated on the surfaces of the first and second polarizing layers facing the first and second substrates, respectively.
- the first and second viewing angle compensating layers are preferably formed on the plate surfaces of the first and second retardation plates, respectively.
- the broadcasting receiving apparatus includes: a broadcasting receiving section to receive broadcasted broadcast waves and to demodulate the received waves to output a demodulation signal having at least picture data and audio data; a picture/audio data generating section to separate the picture data and the audio data from the demodulation signal output from the broadcasting receiving section and to output a picture data and an audio data based on the demodulation signal; a picture display section to drive a plurality of pixels aligned in a matrix based on the picture data supplied from the picture/audio data generating section to display pictures; and a liquid crystal display device.
- the liquid crystal display device includes: a first substrate having, on one surface thereof, at least one first electrode and an alignment film covering the first electrode; a second substrate that is arranged to face an electrode formation surface of the first substrate, and has, on a surface thereof facing the first substrate, a plurality of second electrodes in which regions respectively facing the first electrode form a plurality of pixels aligned in a matrix to form images and an alignment film covering these electrodes; a liquid crystal layer that is sandwiched between the first and second substrates and includes liquid crystal molecules twist-aligned at substantially 90°; first and second polarizing plates that are arranged on both sides of the liquid crystal cell, each of the polarizing plates including a polarizing layer having a transmission axis allowing transmission of linear polarized light and an absorption axis in a direction perpendicular to the transmission axis, and at least one base film to support the polarizing layer; and first and second viewing angle compensating plates that are respectively arranged between the liquid crystal cell and the first and second polarizing plates, each
- the broadcasting receiving section includes: a tuner section to receive a wirelessly broadcasted digital broadcasting signal; and a demodulating section to demodulate the received digital broadcasting signal to a multiple signal including at least picture data and audio data
- the picture/audio data generating section includes a picture/audio decoding processing section to separate the picture data and the audio data from the multiple signal and to decode the separated data to generate a picture data and an audio data.
- the first substrate is provided with a first alignment film covering the first electrode and subjected to an aligning treatment in a predetermined first direction
- the second electrodes is provided with a second alignment film covering the second electrode and subjected to an aligning treatment in a second direction that crosses the first direction at an angle of substantially 90°
- the first polarizing plate includes a first polarizing layer that has an absorption axis in a direction crossing the aligning treatment direction of the first alignment film at an angle of substantially 45° and a base film formed of a resin film that is provided on a surface of the first polarizing layer facing at least the first substrate and has a retardation in a thickness direction, which is a product of a phase difference within a plane perpendicular to substrate surfaces of the first and second substrates and a layer thickness
- the second polarizing plate includes a second polarizing layer that has an absorption axis in a direction substantially perpendicular to or substantially parallel to the absorption axis of the first polarizing layer and a
- a total value of the retardation values in the thickness direction each of which is a product of a phase difference within a plane perpendicular to the substrate surfaces and a layer thickness, of a plurality of optical layers arranged between the first polarizing layer of the first polarizing plate and the second polarizing layer of the second polarizing plate, the plurality of optical layers including the base films on the surfaces of at least the first and second polarizing plates facing the first and second substrates, the respective viewing angle compensating layers of the first and second viewing angle compensating plates, and the base films of the first and second viewing angle compensating plates but excluding the liquid crystal layer, and a retardation value in a liquid crystal layer thickness direction, which is a product of a phase difference within a plane perpendicular to the substrate surfaces and a liquid crystal layer thickness, of the liquid crystal layer when a voltage sufficiently high to raise and align the liquid crystal molecules with respect to the substrate surfaces is applied between the electrodes of the first and second substrates is set to the range of ⁇ 80 n
- the retardation in the liquid crystal layer thickness direction of the liquid crystal display device is a value calculated by multiplying a value of a product ⁇ nd of an anisotropic refractive index ⁇ n of a liquid crystal material constituting the liquid crystal layer and a liquid crystal layer thickness d by a coefficient in the range of 0.72 to 0.89 selected in accordance with a pre-tilt angle of the liquid crystal molecules with respect to the substrate surfaces and a value of the voltage sufficiently high to raise and align the liquid crystal molecules.
- a total value of in-plane retardations of the plurality of optical layers between the first and second polarizing layers, including the plurality of base films, the plurality of viewing angle compensating layers, and the liquid crystal layer is preferable for a total value of in-plane retardations of the plurality of optical layers between the first and second polarizing layers, including the plurality of base films, the plurality of viewing angle compensating layers, and the liquid crystal layer, to be set to the range of 350 nm to 600 nm, the in-plane retardation being a product of an in-plane phase difference within a plane parallel to the substrate surfaces and a layer thickness of each of the plurality of optical layers.
- a first retardation plate to be arranged between the first polarizing layer and the first viewing angle compensating layer and a second retardation plate to be arranged between the second polarizing layer an the second viewing angle compensating layer.
- the broadcasting receiving apparatus includes: a broadcasting receiving section to receive broadcasted broadcast waves and to demodulate the received waves to output a demodulation signal having at least picture data and audio data; an picture/audio data generating section to separate the picture data and the audio data from the demodulation signal output from the broadcasting receiving section and to output a picture data and an audio data based on the demodulation signal; a picture display section to drive a plurality of pixels aligned in a matrix based on the picture data supplied from the picture/audio data generating section to display pictures; and a liquid crystal display device.
- the liquid crystal display device includes: a first substrate having, on one surface thereof, at least one first electrode and a first alignment film covering the first electrode and subjected to an aligning treatment in a predetermined first direction; a second substrate that is arranged to face an electrode formation surface of the first electrode, and has, on a surface thereof facing the first substrate, a plurality of second electrodes in which regions respectively facing the first electrode form a plurality of pixels aligned in a matrix to form images and a second alignment film covering the second electrode and subjected to an aligning treatment in a second direction crossing the first direction at an angle of substantially 90°; a liquid crystal layer that is sandwiched between the first alignment film of the first substrate and the second alignment film of the second substrate and includes liquid crystal molecules twist-aligned between the first alignment film and the second alignment film at a twisted angle of substantially 90°; a first polarizing layer that is arranged to face an outer surface opposite to the electrode formation surface of the first substrate and has an absorption axis in a direction crossing an aligning treatment direction
- the broadcasting receiving apparatus further includes an audio generating section to generate the audio signal based on the audio
Abstract
Description
- This application is based upon and claims the benefit of priority from prior Japanese Patent Applications No. 2007-016655, filed Jan. 26, 2007; No. 2007-125782, filed May 10, 2007; and No. 2008-008077, filed Jan. 17, 2008, the entire contents of all of which are incorporated herein by reference.
- 1. Field of the Invention
- The present invention relates to a television receiver to receive broadcast waves to display pictures.
- 2. Description of the Related Art
- A flat-screen liquid crystal television receiver using a liquid crystal display device to reduce its depth is known as a broadcasting receiver that receives a television broadcast to display its pictures.
- Liquid crystal display devices used in this liquid crystal television receiver include a twisted nematic type liquid crystal display device (a TN liquid crystal display device) in which liquid crystal molecules are twist-aligned between substrates facing each other, a vertical alignment type liquid crystal display device (VA) having a liquid crystal layer in which liquid crystal molecules are vertically initially aligned between substrates, an in-plane switching type liquid crystal device (IPS) in which directions of liquid crystal molecules are controlled within a plane parallel to substrate surfaces, and others.
- Of these liquid crystal devices, as a TN type liquid crystal display device, there is known a liquid crystal display device that includes a liquid crystal cell including a liquid crystal layer in which liquid crystal molecules are twist-aligned at a twisted angle of substantially 90° between a pair of substrates, and a pair of polarizing plates arranged to sandwich this liquid crystal cell therebetween, wherein one of the pair of polarizing plates is arranged in such a direction that an absorption axis is set to parallel with a direction crossing an aligning treatment direction of one substrate of the liquid crystal cell at 45° (see JP-A 2006-285220 (KOKAI)).
- This TN liquid crystal display device enhances contrast and improves grayscale inversion in an intermediate gradation. Further, in this liquid crystal display device, viewing angle compensating plates are respectively arranged between the liquid crystal cell and the pair of polarizing plates, and arranging a retardation plate improves viewing angle characteristics. Further, since these TN liquid crystal display devices have simple structures and matured manufacturing processes, they are good display devices allowed to be mass-produced with stable characteristics.
- However, the TN type liquid crystal display device has large viewing angle dependency of a transmittance as a television receiver observed from various directions, and hence sufficiently wide viewing angle characteristics cannot be obtained.
- An object of the present invention is to provide a liquid crystal display apparatus and a broadcasting receiving apparatus having a wide viewing angle with improved viewing angle dependency of a transmittance.
- A liquid crystal display apparatus according to a first aspect of the present invention includes a liquid crystal display device.
- The liquid crystal display device includes:
- a liquid crystal cell including a pair of substrates in which at least one electrode and an alignment film covering the electrode are provided on each of inner surfaces of the substrates facing each other, and a liquid crystal layer that is sandwiched between the substrates and includes liquid crystal molecules twist-aligned;
- first and second polarizing plates that are arranged on both sides of the liquid crystal cell, each of the polarizing plates including a polarizing layer having a transmission axis allowing transmission of linear polarized light and an absorption axis in a direction perpendicular to the transmission axis, and at least one base film to support the polarizing layer; and
- first and second viewing angle compensating layers that are respectively arranged between the liquid crystal cell and the first and second polarizing plates, each of the viewing angle compensating layers having a phase difference within a plane parallel to substrate surfaces of the liquid crystal cell and a phase difference within a plane perpendicular to the substrate surfaces.
- A total value of retardations in a thickness direction, each of which is a product of a phase difference within a plane perpendicular to the substrate surfaces and a layer thickness, of a plurality of optical layers between the first and second polarizing layers, including at least the first and second viewing angle compensating layers but excluding the liquid crystal layer, is set to a value that cancels out a retardation in a liquid crystal layer thickness direction, which is a product of a phase difference within a plane perpendicular to the substrate surfaces and a liquid crystal layer thickness, of the liquid crystal layer when a voltage sufficiently high to raise and align the liquid crystal molecules with respect to the substrate surfaces is applied to the liquid crystal layer between the electrodes of the first and second substrates.
- The liquid crystal display apparatus further includes a display driving section to supply signals to electrodes formed on a pair of substrates and to drive the liquid crystal display device based on picture data supplied from the outside.
- Furthermore, a broadcasting receiving apparatus according to a second aspect of the present invention includes:
- a broadcasting receiving section to receive broadcasted broadcast waves and to demodulate the received waves to output a demodulation signal having at least picture data and audio data;
- an picture/audio data generating section to separate the picture data and the audio data from the demodulation signal output from the broadcasting receiving section and to output a picture data and an audio data based on the demodulation signal;
- a picture display section to drive a plurality of pixels aligned in a matrix based on the picture data supplied from the picture/audio data generating section to display pictures; and
- a liquid crystal display device.
- The liquid crystal display device includes:
- a first substrate having, on one surface thereof, at least one first electrode and an alignment film covering the first electrode;
- a second substrate that is arranged to face an electrode formation surface of the first substrate, and has, on a surface thereof facing the first substrate, a plurality of second electrodes in which regions respectively facing the first electrode form a plurality of pixels aligned in a matrix to form images and an alignment film covering these electrodes;
- a liquid crystal layer that is sandwiched between the first and second substrates and includes liquid crystal molecules twist-aligned at substantially 90°;
- first and second polarizing plates that are arranged on both sides of the liquid crystal cell, each of the polarizing plates including a polarizing layer having a transmission axis allowing transmission of linear polarized light and an absorption axis in a direction perpendicular to the transmission axis, and at least one base film to support the polarizing layer; and
- first and second viewing angle compensating plates that are respectively arranged between the liquid crystal cell and the first and second polarizing plates, each of the viewing angle compensating plates having a phase difference within a plane parallel to substrate surfaces of the liquid crystal cell and a phase difference within a plane perpendicular to the substrate surfaces, and
- a total value of retardations in a thickness direction, each of which is a product of a phase difference within a plane perpendicular to the substrate surfaces and a layer thickness, of a plurality of optical layers between the first and second polarizing layers, including at least the first and second viewing angle compensating plates but excluding the liquid crystal layer, is set to a value that cancels out a retardation in a liquid crystal layer thickness direction, which is a product of a phase difference within a plane perpendicular to the substrate surfaces and a liquid crystal layer thickness, of the liquid crystal layer when a voltage sufficiently high to raise and align the liquid crystal molecules with respect to the substrate surfaces is applied between the electrodes of the first and second substrates.
- The broadcasting receiving apparatus further includes an audio generating section to generate the audio signal based on the audio data supplied from the picture/audio data generating section and to produce audio from the audio signal.
- Moreover, a broadcasting receiving apparatus according to a third aspect of the present invention includes:
- a broadcasting receiving section to receive broadcasted broadcast waves and to demodulate the received waves to output a demodulation signal having at least picture data and audio data;
- an picture/audio data generating section to separate the picture data and the audio data from the demodulation signal output from the broadcasting receiving section and to output a picture data and an audio data based on the demodulation signal;
- a picture display section to drive a plurality of pixels aligned in a matrix based on the picture data supplied from the picture/audio data generating section to display pictures; and
- a liquid crystal display.
- The liquid crystal display device includes:
- a first substrate having, on one surface thereof, at least one electrode and a first alignment film covering the first electrode and subjected to an aligning treatment in a predetermined first direction;
- a second substrate that is arranged to face an electrode formation surface of the first electrode, and has, on a surface thereof facing the first substrate, a plurality of second electrodes in which regions respectively facing the first electrode form a plurality of pixels aligned in a matrix to form images and a second alignment film covering the second electrode and subjected to an aligning treatment in a second direction crossing the first direction at an angle of substantially 90°;
- a liquid crystal layer that is sandwiched between the first alignment film of the first substrate and the second alignment film of the second substrate and includes liquid crystal molecules twist-aligned between the first alignment film and the second alignment film at a twisted angle of substantially 90°;
- a first polarizing layer that is arranged to face an outer surface opposite to the electrode formation surface of the first substrate and has an absorption axis in a direction crossing an aligning treatment direction of the first alignment film at an angle of substantially 45°;
- a second polarizing layer that is arranged to face an outer surface opposite to an electrode formation surface of the second substrate and has an absorption axis in a direction substantially perpendicular to or substantially parallel to the absorption axis of the first polarizing layer; and
- first and second viewing angle compensating layers that are respectively arranged between the first substrate and the first polarizing layer and between the second substrate and the second polarizing layer, each viewing angle compensating layer having a phase difference within a plane parallel to substrate surfaces of the first and second substrates and a phase difference within a plane perpendicular to the substrate surfaces.
- In regard to a plurality of optical layers between the first and second polarizing layers including at least the first and second viewing angle compensating layers but excluding the liquid crystal layer, a retardation Rth in a thickness direction is set to the range satisfying the following expression:
-
−80 nm<Rth−0.83Δnd<80 nm - where one and the other of two directions perpendicular to each other within a plane parallel to the substrate surfaces are an X axis and a Y axis, a thickness direction perpendicular to the substrate surfaces is a Z axis, nx is a refractive index in the X axis direction, ny is a refractive index in the Y axis direction, nz is a refractive index in the Z axis direction, d is a layer thickness of the optical layer, Rthi is a retardation in the thickness direction of each optical layer represented as {(nx+ny)/2−nz}·d, Rth is the retardation in the thickness direction obtained by adding values of the retardations Rthi in the thickness direction of the respective optical layers, and Δnd is a product of an anisotropic refractive index Δn of a liquid crystal material constituting the liquid crystal layer and a liquid crystal thickness d; and
- The broadcasting receiving apparatus further includes an audio generating section to generate the audio signal based on the audio data supplied from the picture/audio data generating section and to produce audio from the audio signal.
- Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.
- The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention, and together with the general description given above and the detailed description of the embodiments given below, serve to explain the principles of the invention.
-
FIG. 1 is a schematic perspective view of a broadcasting receiving apparatus showing a first embodiment according to the present invention; -
FIG. 2 is a schematic perspective view showing a structure of a liquid crystal display apparatus used in the broadcasting receiving apparatus according to the first embodiment; -
FIG. 3 is a schematic block diagram showing a structure of, the broadcasting receiving apparatus showing the first embodiment; -
FIG. 4 is a block diagram showing a liquid crystal display apparatus used in the broadcasting receiving apparatus according to the first embodiment; -
FIG. 5 is a schematic cross-sectional view of a liquid crystal display device showing a first embodiment of the present invention; -
FIG. 6 is an enlarged cross-sectional view of a part of a liquid crystal cell; -
FIG. 7 is an enlarged cross-sectional view of a part of a viewing angle compensating plate; -
FIG. 8 is a view showing aligning treatment directions of first and second alignment films, directions of absorption axes of first and second polarizing layers, and directions of optical axes of first and second viewing angle compensating layers in the first embodiment; -
FIG. 9 is a view showing a relationship between a ratio of liquid crystal layer thicknesses dR, dG, and dB of pixel portions of respective colors, i.e., red, green, and blue and a display chromaticity when white is displayed in the liquid crystal display device according to the first embodiment; -
FIG. 10 is a view showing a relationship between Δnd of a liquid crystal layer and a retardation RthLC in a thickness direction of the liquid crystal layer when a saturation voltage is applied in the liquid crystal display device according to the first embodiment; -
FIG. 11 is a view showing a relationship between an in-plane retardation Ro, Δnd of the liquid crystal layer, and a transmittance, the in-plane retardation Ro being obtained by adding respective in-plane retardation values of base films of a plurality of optical layers between the first and second polarizing layers excluding the liquid crystal layer in the liquid crystal display device according to the first embodiment; -
FIGS. 12A to 12D are viewing angle characteristic views at the time of white display TW, black display TB, 50% gradation (a gradation with 50% brightness of white display) display T50, and 20% gradation (a gradation with 20% brightness of white display) display T20 in the liquid crystal display device according to the first embodiment; -
FIGS. 13A to 13D are viewing angle characteristic views at the time of white display TW, black display TB, 50% gradation (a gradation with 50% brightness of white display) display T50, and 20% gradation (a gradation with 20% gradation of white display) display T20 in the liquid crystal display device according to a modification of the first embodiment; -
FIG. 14 is a schematic cross-sectional view of a liquid crystal display device used in a second embodiment of the present invention; -
FIG. 15 is a view showing aligning treatment directions of first and second alignment films, directions of absorption axes of first and second polarizing layers, directions of optical axes of first and second viewing angle compensating layers, and directions of retardation axes of first and second retardation plates in the liquid crystal display device according to the second embodiment; -
FIGS. 16A to 16D are viewing angle characteristic views at the time of white display TW, black display TB, 50% gradation (a gradation with 50% brightness of white display) display T50, and 20% gradation (a gradation with 20% brightness of white display) of display T20 in the liquid crystal display in the liquid crystal display device according to the second embodiment; -
FIG. 17 is a schematic cross-sectional view of a liquid crystal display device used in a third embodiment according to the present invention; -
FIG. 18 is a perspective view for explaining characteristics of an optical film in the liquid crystal display device according to the third embodiment; -
FIG. 19 is a view showing aligning treatment directions of first and second alignment films, directions of absorption axes of first and second polarizing layers, directions of optical axes of first and second viewing angle compensating layers, directions of retardation axes of first and second retardation plates, directions of optical axes of first and second optical films; -
FIGS. 20A to 20D are viewing angle characteristic views at the time of white display TW, black display TB, 50% gradation (a gradation with 50% brightness of white display) display T50, and 20% gradation (a gradation with 20% brightness of white display) display T20 in the liquid crystal display device according to the third embodiment; -
FIG. 21 is a schematic cross-sectional view of a liquid crystal display device used in a fourth embodiment of the present invention; -
FIG. 22 is a view showing aligning treatment directions of first and second alignment films, directions of absorption axes of first and second polarizing layers, directions of optical axes of first and second viewing angle compensating layers, directions of retardation axes of first and second retardation plates, and directions of optical axes of optical films in the liquid crystal display device according to the fourth embodiment; -
FIGS. 23A to 23D are viewing angle characteristic views at the time of white display TW, black display TB, 50% gradation (a gradation with 50% brightness of white display) display T50, and 20% gradation (a gradation with 20% brightness of white display) display T20 in the liquid crystal display device according to the fourth embodiment; -
FIG. 24 is a schematic cross-sectional view of a liquid crystal display device used in a fifth embodiment of the present invention; -
FIG. 25 is a view showing aligning treatment directions of first and second alignment films, directions of absorption axes of first and second polarizing layers, directions of optical axes of first and second viewing angle compensating layers, and directions of retardation axes of first and second retardation plates in the liquid crystal display device according to the fifth embodiment; -
FIGS. 26A to 26D are viewing angle characteristic views at the time of white display TW, black display TB, 50% gradation (a gradation with 50% brightness of white display) display T50, and 20% gradation (a gradation with 20% brightness of white display) display T20 in the liquid crystal display device according to the fifth embodiment; -
FIG. 27 is a schematic cross-sectional view of a liquid crystal display device used in a sixth embodiment according to the present invention; -
FIG. 28 is a view showing aligning treatment directions of first and second alignment films, directions of absorption axes of first and second polarizing layers, directions of optical axes of first and second viewing angle compensating layers, and directions of retardation axes of first and second retardation plates in the liquid crystal display device according to the sixth embodiment; -
FIGS. 29A to 29D are viewing angle characteristic views at the time of white display TW, black display TB, 50% gradation (a gradation with 50% brightness of white display) display T50, and 20% gradation (a gradation with 20% brightness of white display) display T20 in the liquid crystal display device according to the sixth embodiment; -
FIG. 30 is a schematic cross-sectional view of a liquid crystal display device used in a seventh embodiment according to the present invention; -
FIG. 31 is a view showing aligning treatment directions of first and second alignment films, directions of absorption axes of first and second polarizing layers, directions of optical axes of first and second viewing angle compensating layers, and directions of retardation axes of first and second retardation plates in the liquid crystal display device according to the seventh embodiment; and -
FIGS. 32A to 32D are viewing angle characteristic views at the time of white display TW, black display TB, 50% gradation (a gradation with 50% brightness of white display) display T50, and 20% gradation (a gradation with 20% brightness of white display) display T20 in the liquid crystal display device according to the seventh embodiment. -
FIGS. 1 to 4 show a structure of a television broadcasting receiver in a first embodiment according to the present invention. As shown inFIG. 1 , abroadcasting receiver 200 includes awindow 202 formed on a front surface of ahousing 201 in accordance with a liquid crystal display device, andspeakers 300 to produce audio, which are arranged on both sides of thewindow 202. Aswitch group 400, including, e.g., a power supply switch, a channel changeover switch, and a volume adjustment switch, is arranged on an upper portion of thehousing 201. Anantenna 500 to receive broadcast waves is arranged on a rear surface of thehousing 201. - A liquid
crystal display device 100, which is arranged in accordance with thewindow 202 of thehousing 201, includes a pair ofsubstrates optical plates - A
backlight 600 is arranged on an opposite side of an observation side of this liquidcrystal display device 100. Thisbacklight 600 includes alight guiding plate 601, anoptical film 602, which may include a diffusion film and a prism sheet, arranged on surface of thelight guiding plate 601 on the liquidcrystal display device 100 side, areflection film 603 arranged on the opposite side of the observation side of thelight guiding plate 601, and a plurality oflight sources 604, which may be LEDs, aligned on anend face 611 of thelight guiding plate 601. Thisbacklight 600 introduces light emitted from the plurality oflight sources 604 to thelight guiding plate 601 from theend face 611, causing the light to propagate within thelight guiding plate 601. The light that has exited from the opposite side of the observation side of thelight guiding plate 601 is reflected by thereflection film 603 to again enter thelight guiding plate 601, and the light that has exited from an exit surface of thelight guiding plate 601 facing the liquidcrystal display device 100. The light that has exited from the exit surface of thelight guiding plate 601 is diffused by the diffusion film of theoptical film 602 to become light having uniform brightness, and is directed toward the liquidcrystal display device 100 by the prism sheet. Thus, the liquidcrystal display device 100 performs transmission type display by using the light exiting thebacklight 600. -
FIG. 3 shows a structure of a television receiver that receives digital broadcasting in this first embodiment. In thisFIG. 3 , atelevision receiver 200 includes anantenna 500 to receive broadcast waves including a broadcasting signal containing picture data and audio data and a transmission control signal for, e.g., a transmission parameter transmitted from a broadcasting station, atuner section 501 to which the broadcast waves received by thisantenna 500 are supplied, ademodulating section 502 to demodulate the broadcasting signal taken out by thistuner section 501, a picture/audiodecoding processing section 503 to decode the demodulated broadcasting signal, adisplay driving section 504 to drive the liquidcrystal display device 100 based on the decoded picture data, an audiosignal generating section 505 to generate an audio signal based on the audio data and to drive thespeakers 300, a transmissionparameter holding section 506 to store a parameter, and acontrol section 507 to control operations of these respective sections. - The transmission
parameter holding section 506 sets a parameter as information required to take out a frequency of a specified channel in thetuner section 501. The picture/audiodecoding processing section 503 separates picture data and audio data from the demodulated broadcasting signal, and decodes the compressed and/or shuffled data to output the picture data and the audio data. - In the
television receiver 200, thetuner section 501 takes out a frequency of a specified channel from a digital broadcasting signal received by theantenna 500 based on a parameter set by reading the parameter of the specified channel from the transmissionparameter holding section 506 by thecontrol section 507. - The
demodulating section 502 takes out a clock signal included in the digital broadcasting signal having the frequency taken out by thetuner section 501 to demodulate the digital broadcasting signal, and outputs a transport stream. - The picture/audio
decoding processing section 503 decodes the transport stream to output the picture data and the audio data. - The picture data output from a picture/audio data generating section including the picture/audio
decoding processing section 503 is supplied to a picture display section including thedisplay driving section 504 and the liquidcrystal display device 100, a driving signal associated with the picture data is generated by thedisplay driving section 504, and this driving signal is supplied to the liquidcrystal display device 100, thereby displaying a picture. - Further, the audio data output from the picture/audio
decoding processing section 503 is supplied to an audio generating section including the audiosignal generating section 505 and thespeakers 300, an audio signal is generated by the audiosignal generating section 505, and the speakers are driven based on this audio signal, thereby reproducing audio. - As shown in
FIG. 4 , the picture display section includes the liquidcrystal display device 100, a dataline driving circuit 534, a scanline driving circuit 524, a opposedelectrode driving circuit 544, and a drivingcontrol circuit 514 to control operations of these circuits. - The liquid
crystal display device 100 in this embodiment is, e.g., an active matrix type liquid crystal display device, and includes a liquid crystal cell including a pair of substrates in which at least one electrode and an alignment film covering the electrode are provided on each of inner surfaces of the substrates, and a liquid crystal layer that is sandwiched between the substrates and includes liquid crystal molecules twist-aligned at substantially 90°. One of the pair of substrates is provided with, on its substrate surface, at least one opposed electrode, and the other substrate is provided with, on its substrate surface facing the opposed electrode, a plurality of pixel electrodes in which regions respectively facing the opposed electrode form a plurality of pixels aligned in a matrix to form images. Furthermore, although not shown, a plurality of thin film transistors formed of TFTs associated with the pixel electrodes are arranged on the other substrate, and a plurality ofdata lines 110 connecting drain electrodes of the thin film transistors in accordance with each column and a plurality ofgate lines 120 connecting gate electrodes of the thin film transistors in accordance with each row are arranged. - The data lines 110 of the liquid
crystal display device 100 are respectively connected with thedata driving circuit 534, thegate lines 120 are respectively connected with the scanline driving circuit 524, and the opposed electrode is connected with the opposedelectrode driving circuit 544. The drivingcontrol circuit 514 generates an image signal based on picture data supplied from the picture/audiodecoding processing section 503, and supplies it together with a control signal, e.g., a clock signal to the data line drivingcircuit 534. The data line drivingcircuit 534 generates a driving signal associated with eachdata line 110 based on the supplied image signal, and applies it to eachdata line 110. The scanline driving circuit 524 generates a scan signal associated with eachscan line 120 based on the control signal supplied from the drivingcontrol circuit 514, and supplies it to eachgate line 120. - As explained above, in the liquid
crystal display device 100, the plurality ofgate lines 120 are sequentially scanned by the scanline driving circuit 524, the driving signal corresponding to the picture data is supplied to eachdata line 110 from the data line drivingcircuit 534 in synchronization with this scanning, and a voltage associated with the driving signal is applied to each pixel, thereby displaying a desired picture. -
FIGS. 5 to 12 show a detailed structure of a liquid crystal display device used in a first embodiment according to the present invention, andFIG. 5 is a schematic cross-sectional view of the liquid crystal display device. - This liquid crystal display device is a TN type liquid crystal display device including a
liquid crystal cell 1 including a nematicliquid crystal layer 10 in which liquid crystal molecules are twist-aligned at a twisted angle of substantially 90° sandwiched between a pair oftransparent substrates polarizing plates liquid crystal cell 1, and first and second viewingangle compensating plates liquid crystal cell 1 and the pair ofpolarizing plates -
FIG. 6 is an enlarged cross-sectional view of a part of theliquid crystal cell 1. Thisliquid crystal cell 1 includes afirst substrate 2, asecond substrate 3 arranged to face this first substrate, and aliquid crystal layer 10 arranged between the first and second substrates. Thefirst substrate 2 has at least one firsttransparent electrode 4 and afirst alignment film 7 that covers thefirst electrode 4 and is subjected to aligning treatment in a predetermined first direction, the firsttransparent electrode 4 and thefirst alignment film 7 being provided on one surface thereof. Thesecond substrate 3 is arranged to face an electrode formation surface of thefirst substrate 2, and has at least one secondtransparent electrode 5 facing thefirst electrode 4, and asecond alignment film 8 that covers the secondtransparent electrode 5 and is subjected to an aligning treatment in a second direction crossing the first direction for covering thesecond electrode 5 at an angle of substantially 90°, the secondtransparent electrode 5 and thesecond alignment film 8 being provided on a surface facing thefirst substrate 2. Theliquid crystal layer 10 is sandwiched between thefirst alignment film 7 and thesecond alignment film 8, andliquid crystal molecules 10 a are twist-aligned at a twisted angle of substantially 90° between thefirst alignment film 7 and thesecond alignment film 8. Thisliquid crystal layer 10 optically rotates a polarized light that has entered in an initial alignment state ofliquid crystal molecules 10 a at 90°. Moreover, thisliquid crystal layer 10 apparently changes a value of a retardation produced with respect to transmitted light within the range of substantially λ/2 in accordance with an alignment state of theliquid crystal molecules 10 a. - This
liquid crystal cell 1 is an active matrix liquid crystal cell, and theelectrode 4 provided on the substrate (which will be referred to as a rear substrate hereinafter) 2, located on an opposite side of a display observation side, is formed of a plurality of pixel electrodes aligned in a matrix, in a row direction (a lateral direction of a screen) and a column direction (the lateral direction of the screen). Theelectrode 5 provided on the other substrate (which will be referred to as a front substrate hereinafter) 3, located on the observation side, is a single-film-like opposed electrode formed to face an entire arrangement region of the plurality ofpixel electrodes 4. - Although omitted in
FIG. 6 , a plurality of TFTs (thin film transistors) respectively arranged in accordance with the plurality ofpixel electrodes 4, a plurality of scanning lines through which gate signals are supplied to the plurality of TFTs in respective rows, and a plurality of signal lines through which data signals are supplied to the plurality of TFTs in respective columns are provided on a surface of therear substrate 2 facing thefront substrate 3. - The TFT includes a gate electrode formed on the
rear substrate 2, a gate insulating film formed to cover the gate electrode, an i-type semiconductor film formed on the gate insulating film to face the gate electrode, and a drain electrode and a source electrode formed on both side portions of the i-type semiconductor film through an n-type semiconductor film. The gate electrode is connected with the scanning line, the drain electrode is connected with the signal line, and the source electrode is connected with the correspondingpixel electrode 4. - Additionally,
color filters front substrate 3 facing therear substrate 2 in accordance with a plurality of pixels formed of regions where the plurality ofpixel electrodes 4 face theopposed electrode 5, and theopposed electrode 5 is provided to cover thecolor filters - Further, the pair of
substrates FIG. 5 ) formed into a frame shape surrounding an arrangement region of the plurality ofpixel electrodes 4. Theliquid crystal layer 10 is encapsulated in a region between the pair ofsubstrates member 9. - Furthermore, as to the
color filters green filter 6G is formed to be thicker than thered filter 6R and theblue filter 6B is formed with a larger film thickness than that of thegreen filter 6G, so that a liquid crystal layer thickness dR of one of the pixels to which thered filter 6R is provided, a liquid crystal layer thickness dG of one of the pixels to which thegreen filter 6G is provided, and a liquid crystal layer thickness dB of one of the pixels to which theblue filter 6B is provided have a relationship of dR<dG<dB. - A ratio of the liquid crystal layer thickness dR of the pixel to which the
red filter 6R is provided, the liquid crystal layer thickness dG of the pixel to which thegreen filter 6G is provided, and the liquid crystal layer thickness dB of the pixel to which theblue filter 6B is provided is set to dR:dG:dB=1.1:1.0:0.9. - Moreover, of the pair of polarizing plates arranged to sandwich the
liquid crystal cell 1 therebetween, the firstpolarizing plate 11 arranged to face an outer surface of theliquid crystal cell 1 opposite to the electrode formation surface of therear substrate 2 is arranged so that its absorption axes is set to parallel with a direction crossing an aligning treatment direction of thefirst alignment film 7 formed on therear substrate 2 at an angle of substantially 45°. The secondpolarizing plate 15 arranged to face an outer surface of theliquid crystal cell 1 opposite to the electrode formation surface of thesubstrate 3 is arranged so that its absorption axes is set to parallel with a direction crossing the aligning treatment direction of thesecond alignment film 8 formed on thefront substrate 3 at an angle of substantially 45°. That is, the absorption axes of the firstpolarizing plate 11 and the secondpolarizing plate 15 are perpendicular to each other. - The first
polarizing plate 11 includes a firstpolarizing layer 12 having an absorption axes in a direction crossing the aligning treatment direction of thefirst alignment film 7 at an angle of substantially 45°, and a pair ofbase films polarizing layer 12 to sandwich the firstpolarizing layer 12 therebetween, have a phase difference in a plane parallel to substrate surfaces of the pair ofsubstrates substrates 2 and 3 (which will be referred to as a phase difference in a thickness direction thereinafter), and are formed of a transparent resin film, e.g., a TAC (triacetylcellulose) film. The secondpolarizing plate 15 includes a secondpolarizing layer 16 having an absorption axis in a direction crossing the aligning treatment direction of thesecond alignment film 8 formed on thefront substrate 8 at an angle of substantially 45°, and a pair ofbase films polarizing layer 16 to sandwich this secondpolarizing layer 16 therebetween, have a phase difference in a plane parallel to the substrate surfaces being substantially zero, have a phase difference in a plane perpendicular to the substrates (a phase difference in the thickness direction), and are formed of a transparent resin film, e.g., a TAC film. - The first and second viewing
angle compensating plates liquid crystal cell 1 and the pair ofpolarizing plates angle compensating layers base films base films 21 being provided on at least one surface of the viewingangle compensating layers 20 and thebase films 24 being provided on at least one surface of the viewing angle compensating layers 23. Each of the viewingangle compensating layers base films - The first and second viewing
angle compensating plates base film angle compensating layer -
FIG. 7 is an enlarged cross-sectional view of a part of the first and second viewingangle compensating plates base films alignment films alignment film 21 a being formed on one surface of thebase film 21 and thealignment film 24 a being formed on one surface of thebase film 24, and the discotic liquid crystal layers are respectively provided on thealignment films liquid crystal molecules 25 are hybrid-aligned so that a molecular axis perpendicular to discotic surfaces of the discoticliquid crystal molecules 25 is placed on a plane perpendicular to a film surface of thebase film 21 and parallel to the aligning treatment direction of thealignment film 21 a and a tilt angle with respect to thebase film 21 is sequentially increased from thebase film 21 side toward its opposite side. - Each of the viewing
angle compensating layer angle compensating plate liquid crystal molecules 25 are present. Here, a line on which the plane where the molecular axes of the discoticliquid crystal molecules 25 are present crosses the surface of the viewingangle compensating layer - Furthermore, the first viewing
angle compensating plate 19 is arranged so that a surface of the first viewingangle compensating layer 20 of this viewingangle compensating plate 19 where a tilt angle of the discoticliquid crystal molecules 25 is large (a surface opposite to thebase film 21 side) faces the outer surface of therear substrate 2 of theliquid crystal cell 1. Moreover, the optical axis direction of the first viewingangle compensating layer 20 is set to parallel with a direction substantially parallel to or substantially perpendicular to the aligning treatment direction of thefirst alignment film 7 formed on therear substrate 2. The second viewingangle compensating plate 22 is arranged so that a surface of the second viewingangle compensating layer 23 of this viewingangle compensating plate 22 where a tilt angle of the discotic liquid crystal molecules is large (a surface opposite to thebase film 24 side) faces the outer surface of thefront substrate 3 of theliquid crystal cell 1. Additionally, the optical axis direction of the second viewingangle compensating layer 23 is set to parallel with a direction substantially parallel to or substantially perpendicular to the aligning treatment direction of thesecond alignment film 8 formed on thefront substrate 3. -
FIG. 8 shows aligningtreatment directions second alignment films liquid crystal cell 1, directions ofabsorption axes polarizing layers polarizing plates optical axis directions angle compensating layers angle compensating plates - As shown in
FIG. 8 , thefirst alignment film 7 formed on therear substrate 2 of theliquid crystal cell 1 is aligned in a first direction crossing a lateral axis direction (a direction indicated by an alternate long and short dash line in the drawing) of a screen of the liquid crystal display device counterclockwise as seen from the observation side at an angle of substantially 45°. Thesecond alignment film 8 formed on thefront substrate 3 is aligned in a second direction (a direction crossing the lateral axis direction of the screen clockwise as seen from the observation side at an angle of substantially 45°) crossing the first direction at an angle of substantially 90°. Theliquid crystal molecules 10 a in theliquid crystal layer 10 held between thefirst alignment film 7 of therear substrate 2 and thesecond alignment film 8 of thefront substrate 3 are twistaligned in a layer thickness direction of theliquid crystal layer 10 between thefirst alignment film 7 and thesecond alignment film 8 at a twisted angle of substantially 90° as indicated by an arrow of a dashed line that shows a twisted direction of a molecular orientation. - In the
liquid crystal layer 10 of thisliquid crystal cell 1, a value of a retardation apparently varies in the range of substantially λ/2 with respect to transmitted light in accordance with an alignment state of theliquid crystal molecules 10 a that changes in accordance with a voltage applied to theliquid crystal layer 10 between theelectrodes substrates - The first
polarizing plate 11 facing the outer surface of therear substrate 2 of theliquid crystal cell 1 is arranged so that theabsorption axis 12 a of the firstpolarizing layer 12 of thispolarizing plate 11 is set to parallel with a direction crossing the lateral axis direction of the screen clockwise as seen from the observation side at an angle of substantially 90°, i.e., crossing the aligningtreatment direction 7 a of thefirst alignment film 7 of therear substrate 2 clockwise as seen from the observation side at an angle of substantially 45°. The secondpolarizing plate 15 facing the outer surface of thefront substrate 3 of theliquid crystal cell 1 is arranged so that theabsorption axis 16 a of the secondpolarizing layer 16 of thispolarizing plate 15 is set to parallel with a direction (a direction substantially parallel with the lateral axis direction of the screen) substantially perpendicular to theabsorption axis 12 a of thepolarizing layer 12 of the firstpolarizing plate 11. - Further, the first viewing
angle compensating plate 19 between therear surface 2 of theliquid crystal cell 1 and the firstpolarizing plate 11 is arranged so that theoptical axis direction 20 a of the first viewingangle compensating layer 20 of this viewingangle compensating plate 19 is set to parallel with a direction substantially parallel with the aligningtreatment direction 7 a of thefirst alignment film 7 of therear substrate 2. The second viewingangle compensating plate 22 between thefront substrate 3 of theliquid crystal cell 1 and the secondpolarizing plate 15 is arranged so that theoptical axis direction 23 a of the second viewingangle compensating layer 23 of this viewingangle compensating plate 22 is set to parallel with a direction substantially parallel with the aligningtreatment direction 8 a of thesecond alignment film 8 of thefront substrate 3, i.e., a direction substantially perpendicular to theoptical axis direction 20 a of the viewingangle compensating layer 20 of the first viewingangle compensating plate 19. - This liquid crystal display device controls transmission of white illumination light emitted from a non-illustrated surface light source arranged on a rear side thereof (the opposite side of the observation side) by application of a voltage to the
liquid crystal layer 10 between theelectrodes color filters - This liquid crystal display device displays a color image having a good color balance because a ratio of the liquid crystal layer thickness dR of the pixel portion to which the
red color filter 6R of theliquid crystal cell 1 is provided (which will be referred to as a red pixel portion hereinafter), the liquid crystal layer thickness dG of the pixel portion to which thegreen filter 6G is provided (which will be referred to as a green pixel portion hereinafter), and the liquid crystal layer thickness dB of the pixel portion to which theblue filter 6B is provided (which will be referred to as a blue pixel portion) is set to dR:dG:dB=1.1:1.0:0.9. - That is,
FIG. 9 shows a relationship between the ratio of the liquid crystal layer thickness dR, dG, and dB of the pixel portions having the respective colors, i.e., red, green, and blue, and a display chromaticity when light is emitted from each of the pixel portions having the colors, i.e., red, green, and blue, to display a white color. - As shown in
FIG. 9 , comparing examples where the ratio of the liquid crystal layer thicknesses dR, dG, and dB of the pixel portions having red, green, and blue colors is set to dR:dG:dB=0.9:1.0:1.1, dR:dG:dB=1.0:1.0:1.0, and dR:dG:dB=1.1:1.0:0.9 with each other, a white display chromaticity when the ratio of the liquid crystal layer thicknesses dR, dG, and dB of the pixel portions having the respective colors is set to dR:dG:dB=1.1:1.0:0.9 is a chromaticity close to that of light from a light source (white illumination light from the surface light source) as compared with a white display chromaticity when the ratio of the liquid crystal layer thicknesses dR, dG, and dB is set to any other value, and hence a color image having a good color balance is displayed. - It is to be noted that this liquid crystal display device is of a normally white type where the first
polarizing plate 11 and the secondpolarizing plate 15 are arranged so that the absorption axes 12 a and 16 a of the respectivepolarizing layers liquid crystal layer 10 between theelectrodes liquid crystal molecules 10 a in the layer thickness direction of theliquid crystal layer 10 to rise to be aligned substantially perpendicularly with respect to the substrate surfaces (which will be referred to as a saturation voltage) is applied to theliquid crystal layer 10 between theelectrodes - In the
liquid crystal cell 1 having theliquid crystal layer 10 in which theliquid crystal molecules 10 a are twist-aligned with a twisted angle of substantially 90° between the pair ofsubstrates liquid crystal molecules 10 a in theliquid crystal layer 10 near the pair ofsubstrates alignment films liquid crystal layer 10 between theelectrodes liquid crystal molecules 10 a near the pair ofsubstrates liquid crystal molecules 10 a in theliquid crystal layer 10 near thesubstrates - Furthermore, when the saturation voltage is applied to the
liquid crystal layer 10 between theelectrodes liquid crystal layer 10 has a negative phase difference (which will be referred to as a phase difference in the liquid crystal layer thickness direction) in a plane perpendicular to the substrate surfaces. - In the liquid crystal display device in which the first and second
polarizing plates polarizing layers treatment directions alignment films - Thus, in the liquid crystal display device according to this embodiment, the first and second viewing
angle compensating plates polarizing plates liquid crystal cell 1 and therear substrate 2 and thefront substrate 3 of theliquid crystal cell 1 so that the first and second viewingangle compensating plates liquid crystal layer 10 in the plane perpendicular to the substrate surfaces when the saturation voltage (a voltage sufficiently high for theliquid crystal molecules 10 a to rise to be aligned) is applied to theliquid crystal layer 10 between theelectrodes liquid crystal cell 1 is canceled out by the phase differences of the plurality of optical layers within the plane perpendicular to the substrate surfaces. The plurality of optical layers include thebase films polarizing plates liquid crystal cell 1 between the firstpolarizing layer 12 of the firstpolarizing plate 11 and the secondpolarizing layer 16 of the secondpolarizing plate 15, the respective viewingangle compensating layers angle compensating plates base films angle compensating plates - That is, a value of a product of the phase difference of the
liquid crystal layer 10 in the liquid crystal layer thickness direction and the liquid crystal layer thickness (an average value of the liquid crystal layer thicknesses dR, dG, and dB of the pixel portions having the respective colors to which the red, the green, and theblue color filters liquid crystal layer 10 at the time of application of the saturation voltage is canceled out. -
FIG. 10 shows a relationship between a product Δnd of an anisotropic refractive index Δn and the liquid crystal layer thickness d of a liquid crystal material constituting theliquid crystal layer 10 and a liquid crystal layer thickness direction retardation RthLC of theliquid crystal layer 10 when the saturation voltage is applied on the assumption that a pre-tilt angle of theliquid crystal molecules 10 a is 5.5° and the saturation voltage is 4V. The liquid crystal layer thickness direction retardation RthLC of theliquid crystal layer 10 when the saturation voltage is applied varies as shown in the drawing in accordance with a value of the product Δnd of theliquid crystal layer 10. That is, the retardation RthLC in the liquid crystal layer thickness direction linearly varies with respect to a change in a value of the product Δn of theliquid crystal layer 10. Thus, the retardation RthLC is obtained by multiplying the value of the product Δnd of theliquid crystal layer 10 by a coefficient corresponding to an inclination of the straight line depicted inFIG. 10 . - Thus, it is good enough to set an absolute value obtained by adding values of the retardations in the thickness direction of the plurality of optical layers excluding the
liquid crystal layer 10 between the firstpolarizing layer 12 of the firstpolarizing plate 11 and the secondpolarizing layer 16 of the secondpolarizing plate 15 to match with an absolute value obtained by multiplying a value of Δnd of theliquid crystal layer 10 by a coefficient preset in accordance with the pre-tilt angle of theliquid crystal molecules 10 a and the saturation voltage, or set a difference between the respective absolute values to fall within the range of −80 nm to +80 nm. - The next Table 1 shows a relationship between the retardation RthLC in the liquid crystal layer thickness direction of the
liquid crystal layer 10 having theliquid crystal molecules 10 a with a pre-tilt angle and a saturation voltage being changed and a coefficient value that is multiplied with respect to a value Δnd of the liquid crystal layer to calculate a value of the retardation in the thickness direction of each of the plurality of optical layers. -
TABLE 1 Saturation Pre-tilt voltage RthLC Coefficient 0.5° 3 V −299.43 0.72 5.5° 3 V −311.03 0.75 10.5° 3 V −321.85 0.77 0.5° 4 V −338.46 0.81 5.5° 4 V −345.40 0.83 10.5° 4 V −352.11 0.85 0.5° 5 V −358.35 0.86 5.5° 5 V −363.41 0.87 10.5° 5 V −368.32 0.86 - As shown in Table 1, when the pre-tilt angle of the
liquid crystal molecules 10 a falls within the range of 0.50° to 10.50° and the saturation voltage falls within the range of 3V to 5V, a value of the retardation in the liquid crystal layer thickness direction of theliquid crystal layer 10 at the time of applying the saturation voltage is calculated by multiplying a coefficient falling within the range of 0.72 to 0.86 by a value of Δnd of the liquid crystal layer. Here, the value of the retardation in the liquid crystal thickness direction of theliquid crystal layer 10 at the time of applying the saturation voltage and a total value of the retardations in the thickness direction of the plurality of optical layers excluding theliquid crystal layer 10 have substantially the same absolute values, and have opposite signs. - Thus, in this embodiment, the total value of the retardations in the thickness direction of the plurality of optical layers between the first
polarizing layer 12 and the secondpolarizing layer 16 excluding theliquid crystal layer 10 is set to a value obtained by multiplying the value of Δnd of theliquid crystal layer 10 by a coefficient falling within the range of 0.72 to 0.86, and a total value of the values of the retardations in the thickness direction of the plurality of optical layers excluding theliquid crystal layer 10 and the retardation in the liquid crystal layer thickness direction of theliquid crystal layer 10 at the time of applying the saturation voltage is set to fall within the range of 0±80 nm (−80 nm to +80 nm). In this case, as the value of the retardation in the liquid crystal layer thickness direction of theliquid crystal layer 10 at the time of applying the saturation voltage, a value obtained by multiplying a coefficient 0.83 by the value of Δnd of theliquid crystal layer 10. - Additionally,
FIG. 11 shows a transmittance of the liquid crystal display device with respect to a value Ro+Δnd that is obtained by adding an in-plane retardation Ro acquired by adding values of in-plane retardations of the plurality of optical layers excluding theliquid crystal layer 10 between the firstpolarizing layer 12 of the firstpolarizing plate 11 and the second polarizing layer of the second polarizing plate in the liquid crystal display device to the product Δnd of theliquid crystal layer 10. The plurality of optical layers include thebase films polarizing plates liquid crystal cell 1, the viewingangle compensating layers angle compensating plates base films angle compensating plates - Thus, in this embodiment, a value obtained by adding a total value of the in-plane retardations each of which is a product of an in-plane phase difference in a plane parallel to the substrate surfaces of each of the plurality of optical layers between the first
polarizing layer 12 and the secondpolarizing layer 16 and a layer thickness of the optical layer to Δnd of theliquid crystal layer 10 is set to the range of 350 nm to 600 nm, or preferably 480 nm. - In more detail, in the liquid crystal display device according to this embodiment, an optical function of the
base films polarizing layers polarizing plates polarizing layer 12 and the secondpolarizing layer 16 concern visibility of the observer, the plurality of optical layers including thebase films polarizing plates angle compensating layers angle compensating plates base films layers liquid crystal layer 10. - As depicted in
FIG. 18 showing X, Y, and Z coordinates of anoptical medium 100 and refractive indices in respective coordinate axis directions, in regard to each of the plurality of optical layers of theoptical medium 100, assuming that one and the other of two directions perpendicular to each other on a plane parallel to the substrate surfaces are an X axis and a Y axis, a thickness direction perpendicular to the substrate surfaces is a Z axis, a refractive index in the X axis direction is nx, a refractive index in the Y axis direction is ny, a refractive index in the Z axis direction is nz, and a layer thickness of the optical layer is d, a retardation Rthi in the thickness direction of each optical layer is expressed as {(nx+ny)/2−nz}·d. Assuming that Rth is a total retardation in the thickness direction obtained by adding values of the retardations Rthi in the thickness direction of these optical layers and Δnd is a product of an anisotropic refractive index Δn of a liquid crystal material constituting theliquid crystal layer 10 and an average liquid crystal layer thickness d, the total retardation Rth in the thickness direction is set to fall within the range satisfying the following expression: -
Rth=0.83Δnd±80 nm. - That is, the total retardation Rth in the thickness direction is set to fall within the range of 0.83Δnd−80 nm to 0.83Δnd+80 nm.
- Furthermore, in retard to the plurality of optical layers between the first
polarizing layer 12 and the secondpolarizing layer 16, assuming that Roi is an in-plane retardation of each optical layer expressed as (nx−ny)·d and Ro is an in-plane retardation obtained by adding values of in-plane retardations Roi of the respective optical layers, the totalized in-plane retardation Ro is set to the range satisfying the following expression: -
Ro+Δnd=350 nm to 600 nm. - In the liquid crystal display device according to this embodiment, a value of Δnd of the
liquid crystal layer 10 of theliquid crystal cell 1 is 380 nm; values of the retardation Rthi in the thickness direction and the in-plane retardation Roi of the first and the second viewingangle compensating layers base films polarizing layers liquid crystal cell 1 and thebase films angle compensating layers - Thus, the retardation Rth in the thickness direction obtained by adding values of the retardations Rthi in the thickness direction, which is expressed as {(nx+ny)/2−nz}·d, of the plurality of the optical layers between the first
polarizing layer 12 and the secondpolarizing layer 16 excluding theliquid crystal layer 10 is 353 nm, and the in-plane retardation Ro obtained by adding values of the in-plane retardations Roi of the plurality of optical layers is 12 nm. Accordingly, the value 0.83Δnd obtained by multiplying the value of Δnd of theliquid crystal layer 10 by the preferable coefficient 0.83 is 315 nm, and the value 353 nm as the added retardation Rth in the thickness direction falls within the range of a value obtained by adding 80 nm to −315 nm or +315 nm as a value of 0.83Δnd. Furthermore, the value obtained by totalizing the added in-plane retardation Ro and Δnd is 392 nm, and falls within the range of 350 nm to 600 nm that defines the range of Ro+Δnd. - Since this liquid crystal display device has the above-explained structure, angle dependency of the transmittance is improved, and a display wide viewing angle is increased. Further, in the television receiver using this liquid crystal display device, its viewing angle is increased.
-
FIGS. 12A to 12D are viewing angle characteristic views at the time of white display TW, black display TB, 50% gradation (a gradation with 50% brightness of white display) display T50, and 20% gradation (a gradation with 20% brightness of white display) display T20 of the liquid crystal display device.FIG. 12A shows viewing angle characteristics in a right-and-left direction of the screen,FIG. 12B shows viewing angle characteristics in an up-and-down direction of the screen,FIG. 12C shows viewing angle characteristics in a direction from a lower left side to a lower right side of the screen, andFIG. 12D shows viewing angle characteristics in a direction from a lower right side to an upper left side of the screen. - It is to be noted that a negative angle is an angle in the left direction and a positive angle is an angle in the right direction in
FIG. 12A . InFIG. 12B , a negative angle is an angle in the lower direction a positive angle is an angle in the upper direction. InFIG. 12C , a negative angle is an angle in the lower left direction and a positive angle is an angle in the upper right direction. InFIG. 12D , a negative angle is an angle in the lower right direction and a positive angle is an angle in the upper left direction. - As shown in
FIGS. 12A to 12D , the liquid crystal display device has the viewing angle characteristics that the angle dependency of a transmittance in each direction, i.e., the right-and-left direction, the up-and-down direction, the direction from the lower left to the lower right, and the direction from the lower right to the upper left in the screen is improved, i.e., inversion of the intermediate gradation does not occur in a wide angle range in each of these directions. The television receiver using this liquid crystal display device has wide viewing angles in a right-and-left direction, a direction from the lower left to the lower right, and a direction from the lower right to the upper left in particular. - It is to be noted that a value of Δnd of the
liquid crystal layer 10 in theliquid crystal cell 1 is set to 380 nm in the liquid crystal display device, but the value of Δnd of theliquid crystal layer 10 may be set to any other value. -
FIGS. 13A to 13D are viewing angle characteristic views at the time of white display TW, black display TB, 50% gradation display T50, and 20% gradation display T20 in a liquid crystal display device in which a value of Δnd of theliquid crystal layer 10 is set to 505 nm and the other structures are the same as those in the foregoing embodiment.FIG. 13A shows viewing angle characteristics in the right-and-left direction of the screen,FIG. 13B shows viewing angle characteristics in the up-and-down direction of the screen,FIG. 13C shows viewing angle characteristics in the direction from the lower left to the lower right of the screen, andFIG. 13D shows viewing angle characteristics in the direction from the lower right to the upper left of the screen. - As shown in
FIGS. 13A to 13D , the liquid crystal display device according to this modification has viewing angle characteristics that angle dependency of a transmittance in each direction, i.e., the right-and-left direction, the up-and-down direction, the direction from the lower left to the lower right, and the direction from the lower right to the upper left in the screen is improved and inversion of the intermediate gradation does not occur in a wide angle range in each of these directions. Moreover, contrast is higher than that of the liquid crystal display device according to the foregoing embodiment. -
FIGS. 14 to 16 show a second embodiment according to the present invention, andFIG. 14 is a schematic cross-sectional view of a liquid crystal display device used in the second embodiment. - The liquid crystal display device according to this embodiment has a structure where a
first retardation plate 26 is arranged between the firstpolarizing plate 11 and the first viewingangle compensating plate 19 and asecond retardation plate 27 is arranged between the secondpolarizing plate 15 and the second viewingangle compensating plate 22 in the liquid crystal display device according to the first embodiment. A plurality of optical layers between a firstpolarizing layer 12 and a secondpolarizing layer 16 excluding aliquid crystal layer 10 includebase films polarizing layers liquid crystal cell 1, the first and second viewingangle compensating layers base films layers second retardation plates -
FIG. 15 shows aligningtreatment directions second alignment films liquid crystal cell 1, directions ofabsorption axes polarizing layers polarizing plates optical axis directions angle compensating layers angle compensating plates second retardation plates - As shown in
FIG. 15 , the aligningtreatment directions second alignment films liquid crystal cell 1, the directions of the absorption axes 12 a and 16 a of thepolarizing layers polarizing plates optical axis directions angle compensating layers angle compensating plates first retardation plate 26 is arranged so that itsretardation axis 26 a is set to parallel with a direction substantially parallel with theoptical axis direction 20 a of the first viewingangle compensating layer 20 of the first viewingangle compensating plate 19. Thesecond retardation plate 27 is arranged so that itsretardation axis 27 a is set to parallel with a direction substantially parallel with theoptical axis direction 23 a of the second viewingangle compensating layer 23 of the second viewingangle compensating plate 22. - Additionally, in this embodiment, a value of Δnd of the
liquid crystal layer 10 of theliquid crystal cell 1 is set to 420 nm, and values of a retardation Rthi in a thickness direction and an in-plane retardation Roi of each of the first and second viewingangle compensating layers base films polarizing layers 16 facing theliquid crystal cell 1 and each ofbase films angle compensating layers second retardation plates polarizing layer 12 and the secondpolarizing layer 16 excluding theliquid crystal layer 10 and the retardation value in the liquid crystal layer direction of theliquid crystal layer 10 at the time of applying a voltage is set to the range of −80 nm to +80 nm. -
FIGS. 16A to 16D are viewing angle characteristic views at the time of white display TW, black display TB, 50% gradation display T50, and 20% gradation display T20 of the liquid crystal display device according to this embodiment.FIG. 16A shows viewing angle characteristics in a right-and-left direction of a screen,FIG. 16B shows viewing angle characteristics in an up-and-down direction of the screen,FIG. 16C shows viewing angle characteristics in a direction from the lower left to the lower right of the screen, andFIG. 16D shows viewing angle characteristics in a direction from the lower right to the upper left of the screen. - As shown in
FIGS. 16A to 16D , in the liquid crystal display device according to this embodiment, angle dependency of a transmittance in each direction, i.e., the right-and-left direction, the up-and-down direction, the direction from the lower left to the lower right, and the direction from the lower right to the upper left of the screen is improved. Furthermore, this liquid crystal display device has viewing angle characteristics that inversion of the intermediate gradation does not occur in a wide angle range in each of these directions, and a viewing angle is wide and contrast is high in the right-and-left direction, the direction from the lower left to the lower right, and the direction from the lower right to the upper left. -
FIGS. 17 , 19, and 20 show a third embodiment according to the present invention, andFIG. 17 is a schematic cross-sectional view of a liquid crystal display device used in the third embodiment. - The liquid crystal display device according to this embodiment has a structure where first and second
optical films first retardation plate 26 and the first viewingangle compensating plate 19 and between thesecond retardation plate 27 and the second viewingangle compensating plate 22 in the liquid crystal display device according to the second embodiment. A plurality of optical layers between a firstpolarizing layer 12 and a secondpolarizing layer 16 excluding aliquid crystal layer 10 includebase films polarizing layers substrates liquid crystal cell 1, the first and second viewingangle compensating layers base films second retardation plates optical films - As shown in
FIG. 18 , in each of the first and secondoptical films optical medium 100, a relationship between one refractive index nx and the other refractive index ny in two directions x and y perpendicular to each other in a plane parallel to a film surface of each of the first and secondoptical films liquid crystal cell 1, and a refractive index nz in a thickness direction z perpendicular to the film surface (the substrate surfaces of the liquid crystal cell 1) is nx=ny>nz. - That is, each of the first and second
optical films -
FIG. 19 shows aligningtreatment directions second alignment films liquid crystal cell 1, directions ofabsorption axes polarizing layers polarizing plates optical axis directions angle compensating layers angle compensating plates second retardation plates optical axes optical films - As shown in
FIG. 19 , the aligningtreatment directions second alignment films liquid crystal cell 1, the directions of the absorption axes 12 a and 16 a of thepolarizing layers polarizing plates optical axis directions angle compensating layers angle compensating plates - On the other hand, the
first retardation plate 26 is arranged so that itsretardation axis 26 a is set to parallel with a direction crossing a lateral axis direction (a direction indicated by an alternate long and shot dash line in the drawing) of the screen counterclockwise as seen from an observation side at an angle of substantially 110°. Thesecond retardation plate 27 is arranged so that itsretardation axis 27 a is set to parallel with a direction crossing the lateral axis direction of the screen clockwise as seen from the observation side at an angle of substantially 20°, i.e., a direction substantially perpendicular to theretardation axis 26 a of thefirst retardation plate 26. It is to be noted that the directions of theoptical axes optical films liquid crystal cell 1. - Furthermore, in this embodiment, a value of Δnd of the
liquid crystal layer 10 of theliquid crystal cell 1 is set to 385 nm, and values of a retardation Rthi in a thickness direction and an in-plane retardation Roi of each of the first and second viewingangle compensating layers base films polarizing layers 16 facing theliquid crystal cell 1 and each ofbase films angle compensating layers second retardation plates optical films optical film polarizing layer 12 and the secondpolarizing layer 16 excluding theliquid crystal layer 10 and the value of the retardation in the liquid crystal layer thickness direction of theliquid crystal layer 10 is set to the range of 0±80 nm. -
FIGS. 20A to 20D are viewing angle characteristic views at the time of white display TW, black display TB, 50% gradation display T50, and 20% gradation display T20 of the liquid crystal display device according to this embodiment.FIG. 20A shows viewing angle characteristics in a right-and-left direction of a screen,FIG. 20B shows viewing angle characteristics in an up-and-down direction of the screen,FIG. 20C shows viewing angle characteristics in a direction from the lower left to the lower right of the screen, andFIG. 20D shows viewing angle characteristics in a direction from the lower right to the upper left of the screen. - As shown in
FIGS. 20A to 20D , the liquid crystal display device according to this embodiment has viewing angle characteristics that angle dependency of a transmittance in each direction, i.e., the right-and-left direction, the up-and-down direction, the direction from the lower left to the lower right, and the direction from the lower right to the upper left in the screen is improved and inversion of the intermediate gradation does not occur in a wide angle range in each of the these directions. The television receiver using this liquid crystal display device has wide viewing angles in a right-and-left direction, a direction from the lower left to the lower right, and a direction from the lower right to the upper left and also has high contrast in particular. -
FIGS. 21 to 23 show a fourth embodiment according to the present invention, andFIG. 21 is a schematic cross-sectional view of a liquid crystal display device used in the fourth embodiment. - The liquid crystal display device according to this embodiment has a structure where the
optical film 29 provided in the third embodiment is further arranged either between thefirst retardation plate 26 and the first viewingangle compensating plate 19 or between thesecond retardation plate 27 and the second viewingangle compensating plate 22, e.g., between thefirst retardation plate 26 and the first viewingangle compensating plate 19 in the liquid crystal display device according to the second embodiment. A plurality of optical layers between a firstpolarizing layer 12 and a secondpolarizing layer 16 excluding aliquid crystal layer 10 includebase films polarizing layers substrates liquid crystal cell 1, the first and second viewingangle compensating layers base films second retardation plates optical film 29. It is to be noted that other structures of the liquid crystal display device according to this embodiment are substantially the same as those according to the third embodiment. -
FIG. 22 show aligningtreatment directions second alignment films liquid crystal cell 1, directions ofabsorption axes polarizing layers polarizing plates optical axis directions angle compensating layers angle compensating plates second retardation plates optical axis 29 a of theoptical film 29. - As shown in
FIG. 22 , the aligningtreatment directions second alignment films liquid crystal cell 1, the directions of the absorption axes 12 a and 16 a of thepolarizing layers polarizing plates optical axis directions angle compensating layers angle compensating plates retardation axis 26 a of thefirst retardation plate 26, the direction of theretardation axis 27 a of thesecond retardation plate 27 are the same as those in the third embodiment. It is to be noted that the direction of theoptical axis 29 a of theoptical film 29 is perpendicular to substrate surfaces of theliquid crystal cell 1. - Furthermore, in this embodiment, a value of Δnd of the
liquid crystal layer 10 in theliquid crystal cell 1 is set to 386 nm, and values of a retardation Rthi in a thickness direction and an in-plane retardation Roi of each of the first and second viewingangle compensating layers base films layers 16 facing theliquid crystal cell 1 and each of thebase films angle compensating layers second retardation plates optical film 28 is set to −160 nm (an in-plane retardation Roi of thisoptical film 28 is 0). In this manner, a total value of the value of the retardations in the thickness value of the plurality of optical layers between the firstpolarizing layer 12 and the secondpolarizing layer 16 excluding theliquid crystal layer 10 and a value of a retardation in the liquid crystal layer thickness direction of theliquid crystal layer 10 is set to fall within the range of 0±80 nm. -
FIGS. 23A to 23D are viewing angle characteristic views at the time of white display TW, black display TB, 50% gradation display T50, and 20% gradation display T20 of the liquid crystal display device according to this embodiment.FIG. 23A shows viewing angle characteristics in a right-and-left direction of a screen,FIG. 23B shows viewing angle characteristics in an up-and-down direction of the screen,FIG. 23C shows viewing angle characteristics in a direction from the lower left to the lower right, andFIG. 23D shows viewing angle characteristics in a direction from the lower right to the upper left. - As shown in
FIGS. 23A to 23D , the liquid crystal display device according to this embodiment has viewing angle characteristics that angle dependency of a transmittance in each direction, i.e., the right-and-left direction, the up-and-down direction, the direction from the lower left to the lower right, and the direction from the lower right to the upper left is improved and inversion of an intermediate gradation does not occur in a wide angle range in each of the these direction. The television receiver using this liquid crystal display device has wide viewing angles in a right-and-left direction, a direction from the lower left to the lower right, and a direction from the lower right to the upper left and also has high contrast in particular. -
FIGS. 24 to 26 show a fifth embodiment according to the present invention, andFIG. 24 is a schematic cross-sectional view of a liquid crystal display device used in the fifth embodiment. - The liquid crystal display device according to this embodiment has a structure where first and second viewing
angle compensating layers second retardation plates polarizing layer 12 and a secondpolarizing layer 16 excluding aliquid crystal layer 10 includebase films polarizing layers substrates liquid crystal cell 1, the first and second viewingangle compensating layers second retardation plates -
FIG. 25 shows aligningtreatment directions second alignment films liquid crystal cell 1, directions ofabsorption axes polarizing layers polarizing plates optical axis directions angle compensating layers second retardation plates - As shown in
FIG. 25 , the aligningtreatment directions second alignment films liquid crystal cell 1, the directions of the absorption axes 12 a and 16 a of thepolarizing layers polarizing plates optical axis directions angle compensating layers retardation axis 26 a of thefirst retardation plate 26 and the direction of theretardation axis 27 a of thesecond retardation plate 27 are the same as those in the third embodiment. - Moreover, in this embodiment, a value of Δnd of the
liquid crystal layer 10 in theliquid crystal cell 1 is set to 385 nm, and values of a retardation Rthi in a thickness direction and an in-plane retardation Roi of each of the first and second viewingangle compensating layers base films polarizing layers 16 facing theliquid crystal cell 1 are set to Rthi=89 nm and Roi=9 nm. Further, values of a retardation Rthi in the thickness direction and an in-plane retardation Roi of each of the first andsecond retardation plates polarizing layer 12 and the secondpolarizing layer 16 excluding theliquid crystal layer 10 and a retardation value in a liquid crystal layer thickness direction of theliquid crystal layer 10 is set to fall within the range of 0±80 nm. - In the liquid crystal display device according to this embodiment, since the first and second viewing
angle compensating layers second retardation plates base films polarizing layers liquid crystal cell 1 are determined as the base films having the retardations in the thickness direction among the plurality of optical layers between the firstpolarizing layer 12 and the secondpolarizing layer 16. Since the number of the base films having the retardations in the thickness direction is reduced in this manner, the angle dependency of a transmittance is further efficiently improved. -
FIGS. 26A to 26D are viewing angle characteristic views at the time of white display TW, black display TB, 50% gradation display T50, and 20% gradation display T20 of the liquid crystal display device according to this embodiment.FIG. 26A shows viewing angle characteristics in a right-and-left direction of a screen,FIG. 26B shows viewing angle characteristics in an up-and-down direction of the screen,FIG. 26C shows viewing angle characteristics in a direction from the lower left to the lower right of the screen, andFIG. 26D shows viewing angle characteristics of a direction from the lower right to the upper left of the screen. - As shown in
FIGS. 26A to 26D , the liquid crystal display device according to this embodiment has viewing angle characteristics that angle dependency of a transmittance in each direction, i.e., the right-and-left direction, the up-and-down direction, the direction from the lower left to the lower right, and the direction from the lower right to the upper left and inversion of an intermediate gradation does not occur in a wide angle range in each of these directions. The television receiver using this liquid crystal display device has wide viewing angles in a right-and-left direction, a direction from the lower left to the lower right, and a direction from the lower right to the upper left and also has high contrast in particular. -
FIGS. 27 to 29 show a sixth embodiment according to the present invention, andFIG. 27 is a schematic cross-sectional view of a liquid crystal display device used in the sixth embodiment. - The liquid crystal display device according to this embodiment has a structure where
base films polarizing layers substrates liquid crystal cell 1 and first andsecond retardation plates polarizing layers liquid crystal cell 1. A plurality of optical layers between the firstpolarizing layer 12 and the secondpolarizing layer 16 excluding aliquid crystal layer 10 include the first andsecond retardation plates angle compensating layers base films angle compensating layers -
FIG. 28 shows aligningtreatment directions second alignment films liquid crystal cell 1, directions ofabsorption axes polarizing layers optical axis directions angle compensating layers second retardation plates - As shown in
FIG. 28 , the aligningtreatment directions second alignment films liquid crystal cell 1, the directions of the absorption axes 12 a and 16 a of the first and secondpolarizing layers optical axis directions angle compensating layers second retardation plates - Further, in this embodiment, a value of Δnd of a
liquid crystal layer 10 of theliquid crystal cell 1 is set to 420 nm, values of a retardation Rthi in a thickness direction and an in-plane retardation Roi of each of the first and second viewingangle compensating layers base films angle compensating layers second retardation plates polarizing layer 12 and the secondpolarizing layer 16 excluding theliquid crystal layer 10 and a retardation value in a liquid crystal layer thickness direction of theliquid crystal layer 10 is set to fall within the range of 0±80 nm in this manner. - In the liquid crystal display device according to this embodiment, the
base films polarizing layers second retardation plates polarizing layers liquid crystal cell 1. Thus, thebase films angle compensating layers polarizing layer 12 and the secondpolarizing layer 16. Since the number of base films having the retardations in the thickness direction is reduced in this manner, the angle dependency of a transmittance is further effectively improved. -
FIGS. 29A to 29D are viewing angle characteristic views at the time of white display TW, black display TB, 50% gradation display T50, and 20% gradation display T20 of a liquid crystal display device according to this embodiment.FIG. 29A shows viewing angle characteristics in a right-and-left direction of a screen,FIG. 29B shows viewing angle characteristics in an up-and-down direction of the screen,FIG. 29C shows viewing angle characteristics of a direction from the lower left to the lower right of the screen, andFIG. 29D shows viewing angle characteristics in a direction from the lower right to the upper left of the screen. - As shown in
FIGS. 29A to 29D , the liquid crystal display device according to this embodiment has viewing angle characteristics that the angle dependency of a transmittance in each direction, i.e., the right-and-left direction, the up-and-down direction, the direction from the lower left to the lower right, and the direction from the lower right to the upper left of the screen is improved and inversion of an intermediate gradation does not occur in a wide angle range in each of these directions. The television receiver using this liquid crystal display device has wide viewing angles in a right-and-left direction, a direction from the lower left to the lower right, and a direction from the lower right to the upper left and also has high contrast in particular. -
FIGS. 30 to 32 show a seventh embodiment according to the present invention, andFIG. 30 is a schematic cross-sectional view of a liquid crystal display device used in the seventh embodiment. - The liquid crystal display device according to this embodiment has a structure where
base films polarizing layers substrates liquid crystal cell 1, first andsecond retardation plates polarizing layers liquid crystal cell 1, and first and second viewingangle compensating layers second retardation plates liquid crystal cell 1 in the liquid crystal display device according to the second embodiment. A plurality of optical layers between the firstpolarizing layer 12 and the secondpolarizing layer 16 excluding aliquid crystal layer 10 include the first andsecond retardation plates angle compensating layers -
FIG. 31 shows aligningtreatment directions second alignment films liquid crystal cell 1, directions ofabsorption axes polarizing layers optical axis directions angle compensating layers second retardation plates - As shown in
FIG. 31 , the aligningtreatment directions second alignment films liquid crystal cell 1, the directions of the absorption axes 12 a and 16 a of the first and secondpolarizing layers optical axis directions angle compensating layers first retardation plate 26 is arranged so that itsretardation axis 26 a is set to parallel with a direction crossing a lateral axis direction of the screen counterclockwise as seen from an observation side at an angle of substantially 100°. Thesecond retardation plate 27 is arranged so that itsretardation axis 27 a is set to parallel with a direction crossing the lateral axis direction of the screen counterclockwise as seen from the observation side at an angle of substantially 10°, i.e., a direction substantially perpendicular to theretardation axis 26 a of thefirst retardation plate 26. - Further, in this embodiment, a value of Δnd of the
liquid crystal layer 10 of theliquid crystal cell 1 is set to 430 nm, and values of a retardation Rthi in a thickness direction and an in-plane retardation Roi of each of the first and second viewingangle compensating layers second retardation plates polarizing layer 12 and the secondpolarizing layer 16 excluding theliquid crystal layer 10 and a retardation value in a liquid crystal layer thickness direction of theliquid crystal layer 10 is set to fall within the range of 0±80 nm. - In the liquid crystal display device according to this embodiment, the
base films polarizing layers substrates liquid crystal cell 1, the first andsecond retardation plates polarizing layers liquid crystal cell 1, and the first and second viewingangle compensating layers second retardation plates liquid crystal cell 1. Thus, base films having retardations in the thickness direction are eliminated from the plurality of optical layers between the firstpolarizing layer 12 and the secondpolarizing layer 16, and thebase films angle compensating layers -
FIGS. 32A to 32D are viewing angle characteristic views at the time of white display TW, black display TB, 50% gradation display T50, and 20% gradation display T20 of the liquid crystal display device according to this embodiment.FIG. 32A shows viewing angle characteristics in a right-and-left direction of a screen,FIG. 32B shows viewing angle characteristics in an up-and-down direction of the screen,FIG. 32C shows viewing angle characteristics in a direction from the lower left to the lower right of the screen, andFIG. 32D shows viewing angle characteristics in a direction from the lower right to the upper left of the screen. - As shown in
FIGS. 32A to 32D , the liquid crystal display device according to this embodiment has viewing angle characteristics that the angle dependency of a transmittance in each direction, i.e., the right-and-left direction, the up-and-down direction, the direction from the lower left to the lower right, and the direction from the lower right to the upper left of the screen is improved and inversion of the intermediate gradation does not occur in a wide angle range in each of these directions. The television receiver using this liquid crystal display device has wide viewing angles in a right-and-left direction, a direction from the lower left to the lower right, and a direction from the lower right to the upper left and also has high contrast in particular. - Although each of the first and second viewing
angle compensating layers liquid crystal molecules 25 are hybrid-aligned, the first and second viewing angle compensating layers are not restricted to the discotic liquid crystal layer, and it may be formed of a liquid crystal layer in which, e.g., elongated spherical liquid crystal molecules are inclined and aligned in one direction with respect to a plane parallel to the substrate surfaces of theliquid crystal cell 1. - Furthermore, although the liquid crystal display device according to each of the foregoing embodiments is of a normally white type in which the first
polarizing layer 12 and the secondpolarizing layer 16 are arranged so that theirabsorption axes polarizing layer 12 and the secondpolarizing layer 16 are arranged so that theirabsorption axes - Moreover, although the television receiver according to each of the foregoing embodiments is a digital broadcasting receiving apparatus that receives digital broadcast waves, demodulates the digital broadcast waves to output a transport stream, separates a picture signal and an audio signal from this transport stream, and decodes these separated signals to generate picture data and audio data, the present invention is not restricted thereto. The receiving apparatus according to the present invention may be an analog broadcast wave receiving apparatus that receives and demodulates analog broadcast waves, and separates a picture signal and an audio signal from an analog signal having various kinds of signals superimposed thereon to generate the picture signal and the audio signal in accordance with an STNC scheme. In this case, the television receiver using the liquid crystal display device has wide viewing angles.
- As explained above, the liquid crystal display apparatus according to the present invention includes a liquid crystal display device. The liquid crystal display device includes: a liquid crystal cell including a pair of substrates in which at least one electrode and an alignment film covering the electrode are provided on each of inner surfaces of the substrates facing each other, and a liquid crystal layer that is sandwiched between the substrates and includes liquid crystal molecules twist-aligned; first and second polarizing plates that are arranged on both sides of the liquid crystal cell, each of the polarizing plates including a polarizing layer having a transmission axis allowing transmission of linear polarized light and an absorption axis in a direction perpendicular to the transmission axis, and at least one base film to support the polarizing layer; and first and second viewing angle compensating layers that are respectively arranged between the liquid crystal cell and the first and second polarizing plates, each of the viewing angle compensating layers having a phase difference within a plane parallel to substrate surfaces of the liquid crystal cell and a phase difference within a plane perpendicular to the substrate surfaces. A total value of retardations in a thickness direction, each of which is a product of a phase difference within a plane perpendicular to the substrate surfaces and a layer thickness, of a plurality of optical layers between the first and second polarizing layers, including at least the first and second viewing angle compensating layers but excluding the liquid crystal layer, is set to a value that cancels out a retardation in a liquid crystal layer thickness direction, which is a product of a phase difference within a plane perpendicular to the substrate surfaces and a liquid crystal layer thickness, of the liquid crystal layer when a voltage sufficiently high to raise and align the liquid crystal molecules with respect to the substrate surfaces is applied to the liquid crystal layer between the electrodes of the first and second substrates. The liquid crystal display apparatus further includes a display driving section to supply signals to electrodes formed on a pair of substrates and to drive the liquid crystal display device based on picture data supplied from the outside.
- In this liquid crystal display apparatus, it is preferable that one of the pair of substrates is provided with at least one opposed electrode, the other of the pair of substrates is provided with a plurality of pixel electrodes in which regions respectively facing the opposed electrode form a plurality of pixels aligned in a matrix to form images, and the display driving section includes: a scan line driving circuit to supply a scan signal that scans lines at least one by one to the plurality of pixels aligned in the matrix; a data line driving circuit to generate a signal supplied to each of the pixels in accordance with supplied picture data and supply the generated signal to each of the pixels; and a driving control circuit to control operations of the scan line driving circuit and the data line driving circuit.
- Additionally, in the liquid crystal display apparatus, it is preferable for the retardation in the thickness direction of each of the plurality of optical layers and the retardation in the liquid crystal layer thickness direction of the liquid crystal layer to be set so that a value obtained by adding a total value of the retardations in the thickness direction of the plurality of optical layers and the value of the retardation in the liquid crystal layer thickness direction of the liquid crystal layer falls within the range of −80 nm to +80 nm.
- Furthermore, in this liquid crystal display apparatus, it is preferable for the value of the retardation in the liquid crystal layer thickness direction of the liquid crystal layer when a voltage that is sufficiently high to raise and align the liquid crystal molecules is applied and the total value of the retardations in the thickness direction of the plurality of optical layers between the first and second polarizing layers excluding the liquid crystal layer to be set so that a difference between absolute values of these values is not greater than 80 nm and these values have a positive and a negative signs opposite to each other. In this case, it is preferable for the retardation in the liquid crystal layer thickness direction to be a value calculated by multiplying a value of a product Δnd of an anisotropic refractive index Δn of a liquid crystal material constituting the liquid crystal layer and a liquid crystal layer thickness d by a coefficient in the range of 0.72 to 0.89 that is selected in accordance with a pre-tilt angle of the liquid crystal molecules with respect to the substrate surfaces and a value of the voltage that is sufficiently high to raise and align the liquid crystal molecules. Moreover, in regard to each of the plurality of optical layers excluding the liquid crystal layer between the first polarizing layer and the second polarizing layer, assuming that one and the other of two directions perpendicular to each other within a plane parallel to the substrate surfaces are an X axis and a Y axis, a thickness direction perpendicular to the substrate surfaces is a Z axis, a refractive index in the X axis direction is nx, a refractive index in the Y axis direction is ny, a refractive index in the Z axis direction is nz, and a layer thickness of the optical layer is d, it is preferable for a total value of retardations in the thickness direction of the respective optical layer each of which is expressed as {(nx+ny)/2−nz}·d to be set to a value that is substantially equal to a value calculated by multiplying a value of the product Δnd of the anisotropic refractive index Δn of the liquid crystal material constituting the liquid crystal layer and the liquid crystal layer thickness d by a coefficient in the range of 0.72 to 0.89 selected in accordance with a pre-tilt angle of the liquid crystal molecules with respect to the substrate surfaces and a value of the voltage that is sufficiently high to raise and align the liquid crystal molecules. Additionally, it is preferable for the total value of the retardation values in the thickness direction of the respective optical layers between the first and second polarizing layers excluding the liquid crystal layer to be set substantially equal to a value calculated by multiplying the product Δnd of the anisotropic refractive index Δn of the liquid crystal material constituting the liquid crystal layer and the liquid crystal layer thickness d by a coefficient 0.83.
- In the liquid crystal display apparatus according to the present invention, it is preferable for a total value of in-plane retardations of the respective optical layers between the first and second polarizing layers including the liquid crystal layer to be set to the range of 350 nm to 600 nm, the in-plane retardation of each optical layer being a product of an in-plane phase difference within a plane parallel to the substrate surfaces and a layer thickness of each optical layer.
- In the liquid crystal display apparatus according to the present invention, the liquid crystal cell includes: a first substrate having, on one surface thereof, at least one first electrode and a first alignment film covering the first electrode and subjected to an aligning treatment in a predetermined first direction; a second substrate that is arranged to face an electrode formation surface of the first substrate, and has, on a surface facing the first substrate, at least one second electrode facing the first electrode and a second alignment film covering the second electrode and subjected to an aligning treatment in a second direction crossing the first direction at an angle of substantially 90°; and a liquid crystal layer that is twist-aligned and held at a twisted angle of substantially 90° between the first alignment film of the first substrate and the second alignment film of the second substrate. It is preferable for the first polarizing plate has a first polarizing layer to have an absorption axis in a direction crossing an aligning treatment direction of the first alignment film at an angle of substantially 45°, and for the second polarizing plate to have a second polarizing layer having an absorption axis in a direction substantially perpendicular to or substantially parallel to the absorption axis of the first polarizing layer.
- In the liquid crystal display device according to the present invention, each of the first and second polarizing layers preferably includes a base film formed of a resin film that is provided on at least a surface of the polarizing layer facing the first or second substrate and has a retardation in a thickness direction, which is a product of a phase difference within a plane perpendicular to the substrate surfaces and a layer thickness. Each of the first and second viewing angle compensating layers preferably includes a base film formed of a resin film that is provided on at least one surface of the viewing angle compensating layer and has a retardation in the thickness direction, which is a product of a phase difference within a plane perpendicular to the substrate surfaces and a layer thickness. The plurality of optical layers between the first and second polarizing layers excluding the liquid crystal layer preferably include at least the base films on the surfaces of the first and second polarizing layers facing the first and second substrates, the first and second viewing angle compensating layers, and the base films of these viewing angle compensating layers.
- In the liquid crystal display apparatus according to the present invention, it is preferable that a first retardation plate is further arranged between the first polarizing layer and the first viewing angle compensating layer and a second retardation plate is further arranged between the second polarizing layer and the second viewing angle compensating layer. In this case, each of the first and second polarizing layers preferably includes a base film formed of a resin film that is provided on at least the surface of the polarizing layer facing the first or second substrate and has a retardation in the thickness direction, which is a product of a phase difference within a plane perpendicular to the substrate surfaces and a layer thickness, and the first and second viewing angle compensating layers are preferably respectively formed on plate surfaces of the first retardation plate and the second retardation plate. Furthermore, each of the first and second polarizing layers preferably includes a base film formed of a resin film arranged on an outer surface of the polarizing layer opposite to the surface facing the first or second substrate. Each of the first and second viewing angle compensating layers preferably includes a base film formed of a resin film that is provided on at least one surface of the viewing angle compensating layer and has a retardation in the thickness direction, which is a product of a phase difference in a plane perpendicular to the substrate surfaces and a layer thickness. The first and second retardation plates are preferably laminated on the surfaces of the first and second polarizing layers facing the first and second substrates, respectively. Moreover, each of the first and second polarizing layers preferably includes a base film formed of a resin film arranged on the outer surface of the polarizing layer opposite to the surface facing the first or second substrate. The first and second retardation plates are preferably laminated on the surfaces of the first and second polarizing layers facing the first and second substrates, respectively. The first and second viewing angle compensating layers are preferably formed on the plate surfaces of the first and second retardation plates, respectively. Additionally, it is preferable that an optical film is further arranged either between the first retardation plate and the first viewing angle compensating layer or between the second retardation plate and the second viewing angle compensating layer, the optical film having one refractive index nx and the other refractive index in two directions perpendicular to each other within a plane parallel to the substrate surfaces, and a refractive index nz in a thickness direction perpendicular to the substrate surfaces satisfying a relationship of nx=ny>nz.
- The broadcasting receiving apparatus according to the present invention includes: a broadcasting receiving section to receive broadcasted broadcast waves and to demodulate the received waves to output a demodulation signal having at least picture data and audio data; a picture/audio data generating section to separate the picture data and the audio data from the demodulation signal output from the broadcasting receiving section and to output a picture data and an audio data based on the demodulation signal; a picture display section to drive a plurality of pixels aligned in a matrix based on the picture data supplied from the picture/audio data generating section to display pictures; and a liquid crystal display device. The liquid crystal display device includes: a first substrate having, on one surface thereof, at least one first electrode and an alignment film covering the first electrode; a second substrate that is arranged to face an electrode formation surface of the first substrate, and has, on a surface thereof facing the first substrate, a plurality of second electrodes in which regions respectively facing the first electrode form a plurality of pixels aligned in a matrix to form images and an alignment film covering these electrodes; a liquid crystal layer that is sandwiched between the first and second substrates and includes liquid crystal molecules twist-aligned at substantially 90°; first and second polarizing plates that are arranged on both sides of the liquid crystal cell, each of the polarizing plates including a polarizing layer having a transmission axis allowing transmission of linear polarized light and an absorption axis in a direction perpendicular to the transmission axis, and at least one base film to support the polarizing layer; and first and second viewing angle compensating plates that are respectively arranged between the liquid crystal cell and the first and second polarizing plates, each of the viewing angle compensating plates having a phase difference within a plane parallel to substrate surfaces of the liquid crystal cell and a phase difference within a plane perpendicular to the substrate surfaces, and a total value of retardations in a thickness direction, each of which is a product of a phase difference within a plane perpendicular to the substrate surfaces and a layer thickness, of a plurality of optical layers between the first and second polarizing layers, including at least the first and second viewing angle compensating plates but excluding the liquid crystal layer, is set to a value that cancels out a retardation in a liquid crystal layer thickness direction, which is a product of a phase difference within a plane perpendicular to the substrate surfaces and a liquid crystal layer thickness, of the liquid crystal layer when a voltage sufficiently high to raise and align the liquid crystal molecules with respect to the substrate surfaces is applied between the electrodes of the first and second substrates. The broadcasting receiving apparatus further includes an audio generating section to generate the audio signal based on the audio data supplied from the picture/audio data generating section to produce audio from the audio signal.
- In this case, it is preferable that the broadcasting receiving section includes: a tuner section to receive a wirelessly broadcasted digital broadcasting signal; and a demodulating section to demodulate the received digital broadcasting signal to a multiple signal including at least picture data and audio data, and the picture/audio data generating section includes a picture/audio decoding processing section to separate the picture data and the audio data from the multiple signal and to decode the separated data to generate a picture data and an audio data.
- Further, it is preferable that the first substrate is provided with a first alignment film covering the first electrode and subjected to an aligning treatment in a predetermined first direction, the second electrodes is provided with a second alignment film covering the second electrode and subjected to an aligning treatment in a second direction that crosses the first direction at an angle of substantially 90°, the first polarizing plate includes a first polarizing layer that has an absorption axis in a direction crossing the aligning treatment direction of the first alignment film at an angle of substantially 45° and a base film formed of a resin film that is provided on a surface of the first polarizing layer facing at least the first substrate and has a retardation in a thickness direction, which is a product of a phase difference within a plane perpendicular to substrate surfaces of the first and second substrates and a layer thickness, the second polarizing plate includes a second polarizing layer that has an absorption axis in a direction substantially perpendicular to or substantially parallel to the absorption axis of the first polarizing layer and a base film formed of a resin film that is provided on a surface of the second polarizing layer facing at least the second substrate and has a retardation in a thickness direction, which is a product of a phase difference within a plane perpendicular to the substrate surfaces and a layer thickness, each of the first and second viewing angle compensating plates includes a viewing angle compensating layer having a phase difference within a plane parallel to the substrate surfaces and a phase difference within a plane perpendicular to the substrate surfaces and a base film formed of a resin film that is provided on at least one surface of the viewing angle compensating layer and has a retardation in a thickness direction, which is a product of a phase difference within the plane perpendicular to the substrate surfaces and a layer thickness. It is also preferable that a total value of the retardation values in the thickness direction, each of which is a product of a phase difference within a plane perpendicular to the substrate surfaces and a layer thickness, of a plurality of optical layers arranged between the first polarizing layer of the first polarizing plate and the second polarizing layer of the second polarizing plate, the plurality of optical layers including the base films on the surfaces of at least the first and second polarizing plates facing the first and second substrates, the respective viewing angle compensating layers of the first and second viewing angle compensating plates, and the base films of the first and second viewing angle compensating plates but excluding the liquid crystal layer, and a retardation value in a liquid crystal layer thickness direction, which is a product of a phase difference within a plane perpendicular to the substrate surfaces and a liquid crystal layer thickness, of the liquid crystal layer when a voltage sufficiently high to raise and align the liquid crystal molecules with respect to the substrate surfaces is applied between the electrodes of the first and second substrates is set to the range of −80 nm to +80 nm.
- In this broadcasting receiving apparatus, it is preferable for the retardation in the liquid crystal layer thickness direction of the liquid crystal display device to be a value calculated by multiplying a value of a product Δnd of an anisotropic refractive index Δn of a liquid crystal material constituting the liquid crystal layer and a liquid crystal layer thickness d by a coefficient in the range of 0.72 to 0.89 selected in accordance with a pre-tilt angle of the liquid crystal molecules with respect to the substrate surfaces and a value of the voltage sufficiently high to raise and align the liquid crystal molecules.
- Furthermore, it is preferable for a total value of in-plane retardations of the plurality of optical layers between the first and second polarizing layers, including the plurality of base films, the plurality of viewing angle compensating layers, and the liquid crystal layer, to be set to the range of 350 nm to 600 nm, the in-plane retardation being a product of an in-plane phase difference within a plane parallel to the substrate surfaces and a layer thickness of each of the plurality of optical layers.
- Moreover, it is preferable for a first retardation plate to be arranged between the first polarizing layer and the first viewing angle compensating layer and a second retardation plate to be arranged between the second polarizing layer an the second viewing angle compensating layer.
- The broadcasting receiving apparatus according to the present invention includes: a broadcasting receiving section to receive broadcasted broadcast waves and to demodulate the received waves to output a demodulation signal having at least picture data and audio data; an picture/audio data generating section to separate the picture data and the audio data from the demodulation signal output from the broadcasting receiving section and to output a picture data and an audio data based on the demodulation signal; a picture display section to drive a plurality of pixels aligned in a matrix based on the picture data supplied from the picture/audio data generating section to display pictures; and a liquid crystal display device. The liquid crystal display device includes: a first substrate having, on one surface thereof, at least one first electrode and a first alignment film covering the first electrode and subjected to an aligning treatment in a predetermined first direction; a second substrate that is arranged to face an electrode formation surface of the first electrode, and has, on a surface thereof facing the first substrate, a plurality of second electrodes in which regions respectively facing the first electrode form a plurality of pixels aligned in a matrix to form images and a second alignment film covering the second electrode and subjected to an aligning treatment in a second direction crossing the first direction at an angle of substantially 90°; a liquid crystal layer that is sandwiched between the first alignment film of the first substrate and the second alignment film of the second substrate and includes liquid crystal molecules twist-aligned between the first alignment film and the second alignment film at a twisted angle of substantially 90°; a first polarizing layer that is arranged to face an outer surface opposite to the electrode formation surface of the first substrate and has an absorption axis in a direction crossing an aligning treatment direction of the first alignment film at an angle of substantially 45°; a second polarizing layer that is arranged to face an outer surface opposite to an electrode formation surface of the second substrate and has an absorption axis in a direction substantially perpendicular to or substantially parallel to the absorption axis of the first polarizing layer; and first and second viewing angle compensating layers that are respectively arranged between the first substrate and the first polarizing layer and between the second substrate and the second polarizing layer, each viewing angle compensating layer having a phase difference within a plane parallel to substrate surfaces of the first and second substrates and a phase difference within a plane perpendicular to the substrate surfaces. In regard to a plurality of optical layers between the first and second polarizing layers including at least the first and second viewing angle compensating layers but excluding the liquid crystal layer, a retardation Rth in a thickness direction is set to the range satisfying the following expression:
-
−80 nm<Rth−0.83Δnd<80 nm - where one and the other of two directions perpendicular to each other within a plane parallel to the substrate surfaces are an X axis and a Y axis, a thickness direction perpendicular to the substrate surfaces is a Z axis, nx is a refractive index in the X axis direction, ny is a refractive index in the Y axis direction, nz is a refractive index in the Z axis direction, d is a layer thickness of the optical layer, Rthi is a retardation in the thickness direction of each optical layer represented as {(nx+ny)/2−nz}·d, Rth is the retardation in the thickness direction obtained by adding values of the retardations Rthi in the thickness direction of the respective optical layers, and Δnd is a product of an anisotropic refractive index Δn of a liquid crystal material constituting the liquid crystal layer and a liquid crystal thickness d. The broadcasting receiving apparatus further includes an audio generating section to generate the audio signal based on the audio data supplied from the picture/audio data generating section and to produce audio from the audio signal.
- In this broadcasting receiving apparatus, in regard to the plurality of optical layers between the first polarizing layer and the second polarizing layer, assuming that an in-plane retardation of each optical layer represented as (nx−ny)·d is Roi, and an in-plane retardation obtained by adding values of the in-plane retardations of the respective optical layers is Ro, it is preferable for each of the in-plane retardation Ro and Δnd of the liquid crystal layer to be set to the range satisfying Ro+Δnd=350 nm to 600 nm.
- Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.
Claims (23)
−80 nm<Rth−0.83Δnd<80 nm
Ro+Δnd=350 nm to 600 nm,
Applications Claiming Priority (6)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2007-016655 | 2007-01-26 | ||
JP2007016655 | 2007-01-26 | ||
JP2007125782 | 2007-05-10 | ||
JP2007-125782 | 2007-05-10 | ||
JP2008008077A JP4311492B2 (en) | 2007-01-26 | 2008-01-17 | Liquid crystal display element and broadcast receiving apparatus |
JP2008-008077 | 2008-01-17 |
Publications (2)
Publication Number | Publication Date |
---|---|
US20080180604A1 true US20080180604A1 (en) | 2008-07-31 |
US7667802B2 US7667802B2 (en) | 2010-02-23 |
Family
ID=39316157
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US12/009,928 Expired - Fee Related US7667802B2 (en) | 2007-01-26 | 2008-01-23 | Television set using liquid crystal display apparatus having improved viewing angle |
Country Status (9)
Country | Link |
---|---|
US (1) | US7667802B2 (en) |
EP (1) | EP2106567B1 (en) |
JP (1) | JP4311492B2 (en) |
KR (1) | KR101171426B1 (en) |
CN (2) | CN102226857B (en) |
AT (1) | ATE538408T1 (en) |
HK (1) | HK1138648A1 (en) |
TW (1) | TWI385440B (en) |
WO (1) | WO2008091022A1 (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20150153496A1 (en) * | 2013-12-02 | 2015-06-04 | Samsung Electronics Co., Ltd. | Optical film, manufacturing method thereof, and display device including the same |
US10845911B2 (en) * | 2018-02-08 | 2020-11-24 | Samsung Display Co., Ltd. | Force sensor member and display device including the same |
US11392006B2 (en) | 2018-09-04 | 2022-07-19 | Lg Chem, Ltd. | Transmittance-variable device |
Families Citing this family (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US8199283B2 (en) * | 2008-02-27 | 2012-06-12 | Stanley Electric Co., Ltd. | Vertical alignment type liquid crystal display device with viewing angle characteristics improved by disposing optical plates |
JP5544844B2 (en) * | 2009-11-27 | 2014-07-09 | カシオ計算機株式会社 | Liquid crystal display element |
JP5380387B2 (en) * | 2010-07-22 | 2014-01-08 | 株式会社ジャパンディスプレイ | Liquid crystal display |
JP5879278B2 (en) | 2012-01-30 | 2016-03-08 | 富士フイルム株式会社 | Liquid crystal display |
JP5879277B2 (en) * | 2012-01-30 | 2016-03-08 | 富士フイルム株式会社 | Liquid crystal display |
KR102068767B1 (en) * | 2013-01-28 | 2020-01-22 | 엘지디스플레이 주식회사 | 3D Display Device |
JP6359338B2 (en) * | 2014-05-22 | 2018-07-18 | スタンレー電気株式会社 | Liquid crystal display |
JP2017194672A (en) * | 2016-04-18 | 2017-10-26 | 日東電工株式会社 | Liquid crystal display |
CN108927019B (en) * | 2017-05-24 | 2021-03-02 | 北京赛特超润界面科技有限公司 | Preparation method of block copolymer membrane and functional porous membrane hybridized salt difference power generation membrane |
CN113625492A (en) * | 2020-05-06 | 2021-11-09 | 群创光电股份有限公司 | Electronic device |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6307608B1 (en) * | 1999-06-30 | 2001-10-23 | Casio Computer Co., Ltd. | Liquid crystal display having wide viewing angle range |
US20050162593A1 (en) * | 2002-03-08 | 2005-07-28 | Sharp Kabushiki Kaisha | Liquid crystal display device |
US20060238684A1 (en) * | 2005-04-25 | 2006-10-26 | Nitto Denko Corporation | Liquid crystal panel and liquid crystal display apparatus |
Family Cites Families (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2803230B2 (en) | 1989-10-19 | 1998-09-24 | 旭硝子株式会社 | Liquid crystal element, polarization conversion element using the same, and driving method thereof |
CN1035790C (en) * | 1993-02-02 | 1997-09-03 | 洛克威尔国际有限公司 | Compensator for liquid crystal oisplay |
GB2314642A (en) * | 1996-06-26 | 1998-01-07 | Sharp Kk | Twisted nematic liquid crystal device |
JP3863446B2 (en) * | 2002-03-08 | 2006-12-27 | シャープ株式会社 | Liquid crystal display |
JP4687507B2 (en) | 2005-03-09 | 2011-05-25 | カシオ計算機株式会社 | Liquid crystal display element |
-
2008
- 2008-01-17 JP JP2008008077A patent/JP4311492B2/en not_active Expired - Fee Related
- 2008-01-23 US US12/009,928 patent/US7667802B2/en not_active Expired - Fee Related
- 2008-01-24 KR KR1020097015703A patent/KR101171426B1/en not_active IP Right Cessation
- 2008-01-24 WO PCT/JP2008/051593 patent/WO2008091022A1/en active Application Filing
- 2008-01-24 EP EP08710691A patent/EP2106567B1/en not_active Not-in-force
- 2008-01-24 AT AT08710691T patent/ATE538408T1/en active
- 2008-01-24 CN CN201110159526.0A patent/CN102226857B/en not_active Expired - Fee Related
- 2008-01-24 CN CN2008800030885A patent/CN101600988B/en not_active Expired - Fee Related
- 2008-01-25 TW TW097102818A patent/TWI385440B/en not_active IP Right Cessation
-
2010
- 2010-05-28 HK HK10105269.1A patent/HK1138648A1/en not_active IP Right Cessation
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6307608B1 (en) * | 1999-06-30 | 2001-10-23 | Casio Computer Co., Ltd. | Liquid crystal display having wide viewing angle range |
US20050162593A1 (en) * | 2002-03-08 | 2005-07-28 | Sharp Kabushiki Kaisha | Liquid crystal display device |
US20060238684A1 (en) * | 2005-04-25 | 2006-10-26 | Nitto Denko Corporation | Liquid crystal panel and liquid crystal display apparatus |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20150153496A1 (en) * | 2013-12-02 | 2015-06-04 | Samsung Electronics Co., Ltd. | Optical film, manufacturing method thereof, and display device including the same |
US9891359B2 (en) * | 2013-12-02 | 2018-02-13 | Samsung Electronics Co., Ltd. | Optical film, manufacturing method thereof, and display device including the same |
US10845911B2 (en) * | 2018-02-08 | 2020-11-24 | Samsung Display Co., Ltd. | Force sensor member and display device including the same |
US11392006B2 (en) | 2018-09-04 | 2022-07-19 | Lg Chem, Ltd. | Transmittance-variable device |
Also Published As
Publication number | Publication date |
---|---|
CN101600988B (en) | 2011-07-06 |
KR101171426B1 (en) | 2012-08-06 |
JP4311492B2 (en) | 2009-08-12 |
EP2106567A1 (en) | 2009-10-07 |
HK1138648A1 (en) | 2010-08-27 |
CN101600988A (en) | 2009-12-09 |
EP2106567B1 (en) | 2011-12-21 |
US7667802B2 (en) | 2010-02-23 |
JP2008304895A (en) | 2008-12-18 |
TW200839377A (en) | 2008-10-01 |
ATE538408T1 (en) | 2012-01-15 |
WO2008091022A1 (en) | 2008-07-31 |
CN102226857B (en) | 2014-03-05 |
CN102226857A (en) | 2011-10-26 |
TWI385440B (en) | 2013-02-11 |
KR20090094468A (en) | 2009-09-07 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US7667802B2 (en) | Television set using liquid crystal display apparatus having improved viewing angle | |
US7999894B2 (en) | Liquid crystal display device | |
KR100871817B1 (en) | Multiple-panel liquid crystal display device | |
US8009248B2 (en) | Liquid crystal display and television receiver | |
WO2009157245A1 (en) | Liquid crystal display panel and liquid crystal display device | |
CN103713423B (en) | Liquid crystal indicator | |
US8836609B2 (en) | Time type stereoscopic display device and time type stereoscopic image displaying method | |
US7843534B2 (en) | Image display system | |
US6542210B1 (en) | Structure of liquid crystal display | |
JP2010134394A (en) | Stereoscopic display using guest-host liquid crystal | |
US20100165248A1 (en) | Backlight unit and liquid crystal display device having the same | |
JP5115495B2 (en) | Liquid crystal display element and broadcast receiving apparatus | |
US8013958B2 (en) | Liquid crystal device | |
TWI361932B (en) | Liquid crystal display device | |
JP2011064885A (en) | Liquid crystal apparatus and electronic apparatus | |
JP2023124102A (en) | Liquid crystal device, display, and optical modulation module | |
KR100488932B1 (en) | Twisted Nematic LCD Display | |
JP2003248225A (en) | Liquid crystal display device |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: CASIO COMPUTER CO., LTD., JAPAN Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:OHSAWA, KAZUHIKO;YOSHIDA, TETSUSHI;REEL/FRAME:020725/0568 Effective date: 20080201 Owner name: CASIO COMPUTER CO., LTD.,JAPAN Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:OHSAWA, KAZUHIKO;YOSHIDA, TETSUSHI;REEL/FRAME:020725/0568 Effective date: 20080201 |
|
FEPP | Fee payment procedure |
Free format text: PAYOR NUMBER ASSIGNED (ORIGINAL EVENT CODE: ASPN); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY |
|
CC | Certificate of correction | ||
FPAY | Fee payment |
Year of fee payment: 4 |
|
FEPP | Fee payment procedure |
Free format text: PAYOR NUMBER ASSIGNED (ORIGINAL EVENT CODE: ASPN); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY Free format text: PAYER NUMBER DE-ASSIGNED (ORIGINAL EVENT CODE: RMPN); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY |
|
FEPP | Fee payment procedure |
Free format text: MAINTENANCE FEE REMINDER MAILED (ORIGINAL EVENT CODE: REM.) |
|
LAPS | Lapse for failure to pay maintenance fees |
Free format text: PATENT EXPIRED FOR FAILURE TO PAY MAINTENANCE FEES (ORIGINAL EVENT CODE: EXP.) |
|
STCH | Information on status: patent discontinuation |
Free format text: PATENT EXPIRED DUE TO NONPAYMENT OF MAINTENANCE FEES UNDER 37 CFR 1.362 |
|
FP | Lapsed due to failure to pay maintenance fee |
Effective date: 20180223 |